TypeT2 A@SERIAL hmessageIgijSTRING2CgSTRING1=gSTATUSSDEFSROWSYSPEED vSTIME DISP 7gFREE &STIME2 STIME4STIME3dSTIME1FONLINESERIALNO1gc219+gc218%gc217gc216gc215gc214 gc213gc212gc211fc210fc29fc28fc120fc119 fc118!fc117"fc116#fc115$fc114%fc113&fc112'fc111(fc110)fc19*fc18+ftime,fmcol-Gminutes.hcol/Ehours0col1row2year3YID4tcol5month6dcol7day8EPHONE9fDPHONE:fCSZIP;fADDRESS<}fFNAME=wfCOMPANY>qfLNAME?kfadapter@ABQC$DEFGzHWIefJK LMNOP QdfRlScfTbfUafV`fW_fX]fY\fZZf[Xf\Vf]Sf^Qf_Of`LfaIfbCfc=fd=<;:9RL  I   p   E         (  D  D  D  D  I K K i111111RK E ۱  F O R E W O R D  ۱ 9 ۱ Dvorak'sGuidetoPC Telecommunicationsand Modem Tutor ۱ '   You can see samples of what you can do with a modem. Read through ۱ several tutorial articles about protocol, parameters, sysop's view- ۱ points, uploading and downloading files and even experience actual ۱ BBS screens and menus. All this and more, only a keystroke away. ۱G ۱IKQ @ "ͻ111111ͼ2.01aram_u'8797Y'6595Y_tuv`uv^u_]u_p{ezenehegeXeWestart help 8'>)>>0> 0>>)>>0>>0>>)'>b 8 8 #ͻ ) You can call for HELP by pressing ) the F1 key on your keyboard. ) #ͼ bPress Any Key to Continue our keybok=%_V494Yutv_pVeUeeddQdPdMain Menu 3 2187650/.-,+*)('&%$#"! ROM`OOG``a`aD`OOG`` 02a` 0``OOGM`OOLGXO O( ( OGOG OGOG OGOG OG OG OGOG OGOG OGOG  OGOG  OGOG  OGOG OGOG OGOG OGOG OG!OG! O GO GWO> pp p RKĿ Welcome to John C. Dvorak's Guide to PCTelecommunications  00/00/00 (c) Copyright 1989, Computer Business Services 00:00 K Articles 1 Sample Programs 2 * Modem Tutor Introduction  * Telix 3.11 Demo * Authors & Contributors  * Procomm Demo * Modems Introduction  * Qmodem Demo * RS-232 C Standard  * ANSI BBS Screens * Communications Primer  * Sandcastle BBS * Features to Look For  * Fountain Head BBS * Parameters & Protocol  * The Ledge BBS * Understanding 9600Baud  * 1139 BBS * The Sysop Perspective  * Diamond Bar * On-Line Addiction  * AIM BBS - BBS * Archive "Quickstart"  * Laguna Hills BBS * Glossary of Terms  * CHEERS BBS * Credits  * Exit ͼ Select Item & Press Enter On-Line: S/N #0 2.01 F1-help Esc-exitt0.*0,9,"00900YY(0/9/Y(.-9-Yu_CG2w1O12I21;,-P_ _& __H_M_K_ "1hd"2YYfdU2ddVbd+ Vad V`dV_dV^d&V]d,V\d.V[d7VZdIVYdRVXdXVWd\VVd]Q3.}Ud2_Sd_upOdNdddddBanner pZpq4p4pp,$p,$p,$p,$p,ppppNĿ HĿ H  ͻ    Ȼ Telecommunications Guide ɼ     ͼ 0ͻ -  UNDERSTANDING MODEMS & ELECTRONIC MAIL Ȼ. A Modem "Slide Show" . .ͼ H H  ARTICLES PROGRAM EXAMPLES BBS WELCOME SCREENS      GLOSSARY UNDERSTAND 9600 BAUD ON-LINE ADDICTION      PROTOCOL PARAMETERS ERROR CORRECTION  C H Nom KIHD -,C;O&wG 2_.}_pddccccIntro Modem Z^^1^3iKl /2 The Modem Tutor/Demo Disk '  As the popularity of modems has increased, so has the ease of use and features now offered. Today, BBS software offers 'help' screens and an extensive menu system. Although most modems sold today require no "configuration" (they can be plugged in and used with their factory  default settings) there is still confusion about using modems.  O Understanding telecommunications and modems becomes easier when  you see an actual demonstration of the whole process. & * We have created the definitive modem demonstration. Along with demonstrations of modem software and BBS systems are colorful sample ANSI graphics screens common on today's BBS systems. We have also included articles on 9600 bps modems, dual standards and electronic   communications topics with illustrations, and even a glossary of terms. P Qmode+c pcccxcvcucDvorak Bio. 00 0000$0000000000000000000 00 0000000000". M 3 D M 3 8 8o John C. Dvorak was born and raised in  California. A recent study showed John ' the most read computer columnist in the) country, appearing in PC Magazine, PC+ Computing, MacUser and many other news-) papers and magazines. His unique style,( humor and wit have made him an institution  for PC Magazine readers who want the, "Inside Track." > O John is a Mac and PC "power user" who has' managed to cut through the hype of press  releases and advertisements and bringus% keen insights on products to avoid or to' buy.   4^ Qg, M* ptcscMc?c>c=cAnis Bio. ]O1000(010101010101010101010101-". 4 4 4 4 4P  Nick Anis, author, lecturer and industry  insider, has developed several computer  software products and founded three firms. # As a speaker and trainer, he has appeared $ on radio and TV. His courses are enjoyed  by thousands of students and professionals% each year at colleges, universities and % training centers. 7 N Nick is an active online user and is the  sysop for his firm's BBS.V  1 5 5 5 Qr ppI˻͹ACKNOWLEDGEMENTSͼ5 ȹͼ RAM and disk space may limit us mentioning all those who made this project possible. We will forever be in their debt. In the true spirit of BBS fellowship, sysops and users throughout the world pitched in and helped!ZJoe Shepard, SysopColin Sampaleanu, "TELIX"Otto Ruppel, Sysop Dan Bricklin, Software Garden Jim Holloway,SysopChuck Guzis, Sydex SoftwareRob, Brun, Sysop Vernon Buerg,"LIST"Darin May, SysopJohn Friel, "Qmodem" Mark Mahoney, Exec PCPaul Meiners, "GT Powercomm"Steve Harms, SysopMerlin R. Null, "Squawk"Mark Stein, Sysop Phil Katz, PKwareEric Cockrell, EZ-Reader Chuck Forsberg, "ZMODEM"Mike Callahan, Dr. File FinderJustin Boyan, "Boyan"John Weaver, Consultant Jere Greene, Consultant Peter Norton, P.N.C. Mike Weaver, ConsultantMark Smith, US Robotics Mike Kruss, Sysop Jim Harrer, Mustang Software Jeff Pepper, Osborne McGraw-Hill Steve Gibson, Gibson Labs. Cindy Hudson, Osborne McGraw-HillW̻An Expanded Acknowledgement Section can be Found in HELP.TXT ȼJʼ f pb bbzbxbwbSo Modem is...  0301010     @  @  @  @  @  @  @  @  @ @ @  6   So You Want to Use A Modem?       &  You'll  -  Many of you are familiar with the  Get  story of an anthropologist who transplants a   member of a primitive culture into our HOOKED  society. What would be one of the first   tools of modern civilization this person  on  would use? Right, a television. At first   the scientist would use the television to MODEMS!  show tapes helping to acclimate the subject. _ _  One day the subject would discover that the \\/ \  television can also be used to get "programs." //\_/  Like all newcomers to television, our subject would soon discover that there is a "whole world"   of television programming out there. Before too long, our uncivilized friend would be on  a checkout line at Circuit City, purchasing a  VCR with a VISA card. 4D 0 n an) pvb ub%b bbbHardware Setup |  DW7R A si7R A similar process occurs with PC owners. Before too long  they discover that their PC, when connected to a MODEM, can become  a doorway to the exciting world of electronic communications.  H In this exciting world, we can make our own airline reserva-  tions, track Dow Jones quotes, access the encyclopedia, get the  weather report or find out how the Roseanne Barr show did last  night in the Nielsenratings.. H Our book and this tutor will show you how you can call any   one of 15,0 telephone numbers and get thousands of "free"  public domain and low cost shareware programs sent right over the  telephone. 5  A There is a minor obstacle in this exciting doorway. Tele- communications are one of the least standardized operations in the  computer world! Between you and the exciting world of electronic  communications stands a web of tangled wires, switch settings, baud  rates, data bits, stop-bits, cables that have 25 pins but don't use  them, and cables with 9 pins that do. D P  pb baaaaTermin Emular    8W Now what? You have to learn to use a communications program  (Terminal Emulator), and dial up someone/thing.  H Terminal programs may be the easiest application you'll get  to use once you learn the "secrets" of parameters, protocol and  terminal program's phone directory. You will discover using  a "smart" terminal program is a smart idea and using a "dumb"  terminal is a "dumb" one!  UOnce you have your hardware installed and your terminalemulator working, you are ready to try your hand at connecting toand using an electronic bulletin board system. You can try any ofthe commercial online servicessuch as CompuServe and GEnie or one of the thousands of public domain BBS systems.m  BBS (Bulletin Board Systems): The idea behind bulletin boards is the same idea behind the cork bulletin board found at your local grocery store or any public area: to share information. The two methods of sharing information are messages and file transfers.  P program pa avapaoanaMessaging Z;7 / X  K 9 K ͻ 6 ͹ MESSAGING 5  ͼ Electronic messaging is one of the most popular features of  a bulletin board. Most messages are PUBLIC and can be accessed  by any caller. Public messages allow you to communicate with  thousands of people all over the world. PRIVATE messages (Elec-  tronic mail or E-mail) are quickly becoming the method of choice  for business communications. Messages are stored in electronic   mail boxes and only you and the people you authorize have the key to the the box. You can read and reply to, and refer back to,  messages quickly and effortlessly with E-mail!  J Real-Time Conferencing: Sometimes called "CB Simulator,"  conferencing is very addictive. Conferencing is like a CB con-  versation only you "type" and "read" instead of speak and listen.  It is often easier to decide what to say as you can refer back to  the entire conversation as you go along. You will always have  the BACKSPACE key if you change your mind (a feature not found  in most mouths).;P ssaging is  pmala&a aaaFile Transfer Z;7 I  10 I10 I  ͻ7 ͹ FILE TRANSFER: 5 ͼ 8 L The most common way to get information (a file) into your  computer is via "floppy disk." When your brother, who is 3,0  miles away, has a 20-page article he wants you to read, sending a  floppy or hard copy will take at least 24 hours. In a matter of  minutes you can have the file in your computer, ready to read, by  using your modem. 7 I Today, file transfers are used for much more than just  "text." Thousands of programs are available for transfer (upload  or download) on a network of over 15,0 BBSs throughout the  world. There are also thousands of public domain program titles  (both freeware and shareware). In less than one hour, you can   scoop up a talking black jack game, play 100 hands and then get a  copy of the Bible (to reflect on your gambling problem). L P  The most paa`````Q&A Modems 1 ; "    "4JKJ/JJJ= JJJJJ= JJ .:(H , , ˻̼   ͻ  11ȹ ͹ Modems - Questions and Answers  ͼ Where are modems used? 6 O  Everywhere! Cities, small towns, business and personal.c What does ANSI graphics have to do with modems?tMany IBM compatible modem programs use ANSI graphics and colors.]What are parameters, baud rate, data bits, stop bits, parity?fThese are some of the terms you don't have to understand but mustat least be able to set to match the computer to which you are connected. 2ZWhat is protocol? Xmodem, Ymodem, Zmodem, XON/XOFF, Sealink?fA method of sending "blocks" of information with special   error checking. Protocol sends the file intact and is necessary   send/receive files other than straight ASCII text. ̻D  ɹHʼha p``t`]`\`[`Z`Q&A Modems 2 ; "    ".J ;J ;JJ0JJJGG,/JJJC @ H, , ˻̼   ͻ  12ȹ  ͹ Modems - Questions and Answers ͼ ͼInternal vs. External Modems.1  K  Internal: Includes serial port, is machine specific, uses a  slot, has no indicator lights, may have firmware. External: Universal, requires serial port, cable and power   source, has volume control and indicator lights. VWhat are on-line services?, ^ Pay BBS services offering real time access to several commercial database related services. Reference books, airline reservations, news services, message systems, teleconferencing and more. BIX, BSR After Dark, CompuServe, GEnie, Prodigy. ', What is the AT Command Set?+  J   The original Hayes modem used a set of AT commands which have since become the standard for modem commands. "Hayes compatible"   means "uses the Hayes AT command set." AT D= Attention Dial, ̻  AT H= Attention Hang Up, AT S0=2 means answer on 2nd ring. ɹHʼuires  pY`X`````q&a1 Y/+& 13X ͻ* ͹ Why Do You Need A Modem? *  { Just about every business user needs a modem. Today many industries  benefitfrom using modems. If you are working in the accounting area   of a firm, a modem can help transmit payroll or other financial data   to a service bureau, to branch offices or to headquarters.often on   a daily basis.< P  The banking, brokerage or retailing industries, where transactions  are entered directly by computer, are especially heavy users of  modems.> W If you are in the research field.from marketers to librarians.  using a modem will allow you to tap into the wealth of information  available from on-line information services. V The most surprising thing about modems is how people from all walks  of life benefit from their use.*   p``____q&a2 Y%(#$% "14 "  #ͻ(͹ What Speed Should You Be Using? # #ͼ t For occasional or low-volume use, or for interactive sessions with  on-line services, 1200 bps is usually adequate. Because of a small  difference in cost (at today's prices), a 2400 bps modem is usually   the best choice.9  O For frequent transferring of larger volumes of data, a 2400 bps modem   is the the clear choice. In addition, if the information is being  transferred over long distance lines, a 2400 bps modem will quickly pay for itself in lower phone bills.) O For heavy data communications users where time is important or long  distance lines must be used, you can benefit from one of the 9600 bps  modems available today. (See Understanding 9600 bps).  p_____@ > @OMt5 >ͻ15 >ͻ ͹ Don't You Need Special Lines for 2400 and 9600 bps Modems?  >ͼ  In a word, NO! Today 2400 and 9600 bps modems use advanced  filtering, line equalization and modulation techniques to provide transmission over ordinary dial-up phone lines. Most 9600 bps  modems have an automatic fall back to slower speeds in the case  of unusually noisy lines that cause excessive transmission errors. u p__w_s_r_q_q&a3 .*16Q2 16 ͻ.͹ What About Compatibility? ) ͼ  All of the popular 300, 1200 and 2400 bps modems adhere to the industry standard at all their speeds, so they are compatible  with virtually any 300, 1200 or 2400 bps modem now in service.  At 2400 bps, the standard is CCITT V.22 bis. At 1200, Bell 212A,  and at 300, Bell 103.0 Q  For high speed users CCITT V.32, and three others are used. It   is still undecided which of the 3 or 4 conventions will become   the "standard".8 8 pp_C_?_>_=_424 2ͻ17 2ͻ͹ Why All This Interest/Excitement AboutModems?  2ͼ  C H Personal computers are becoming more powerful each day. Today's  hardware and software is far advanced from what was available only a   few years ago Exciting new advances in Video, Graphics, CD ROMS and  other high capacity disk drives represent only a small improvement  compared to on-line communications. Telecommunications - that is computers, talking to computers over telephone lines is the wave of   the future and the possibilities are limitless! _outModems? p<_;__^^^Modem Diagram h$J0J0J0J0J0J0J0J0J0J0J0J0J0W#The 18hThe Basic Elements of Telecomputing:' Basic telecomputing involves four major elements, data, data terminal equipment, data communications equipment and a communications link.ZHͻ Communications Link: G  ? Ŀ Ŀ      DTE Ŀ data data ĴDTE   Ŀ Ŀ Ŀ   ĴDCE ĴDCE   TELEPHONE  COMPUTER MODEM LINES MODEM COMPUTER  GHͼWDTE = Data Terminal Equipment DCE = Data Communications Equipment Rerminal e p^^^^^^Character Chart h#[-#[+#[-#H??????????????????????????????Transm19Transmitted Characters and Parity\Every transmitted character is framed by a start bit and a stop bit, which  tell the receiving system when a byte of data begins and ends. A parity  bit can be added for simple error checking. Today parity is seldom used.11 110 00010  KStopParity/Start Bit  Bit C H A R A C T E R  Bit/MP ror checkin p^^^^^^Errors Chart S*[[[&[[0 *[0 *080808080808080 '[  [[$[''[(()$/20 k /20 Modem #1 Half Duplex #2= Full Duplex ; Transmission errors $ are reduced by use =of parity and CONNECT 2400 #protocol. It is =critical that both hheelloo?? %the sending and wwhhatt''ss ggooiinngg oonn hheerree?? receiving modem be  Looks OK on my end"set" correctly.  K P Modems with Different Transfer RatesCONNECT  |<>~<><><><><><><><><><><><><% ><><><><><><><><><><><><><><><><% <><><><><><><><><><><><><+<><><><><><><><><><><><>><><<>uO the p^^Q^<^:^9^RS232 1 > D B %BB D >    0   33  3 3 3 3 n    0    >˻ ˻>˻ >μ21 @  For the electronics buffs, the next two pages will explain  the most common connection used with modems, the RS-232  serial interface. "Pin Outs" are also provided. >λ ʼ>ʼ ˻˻˻˻˻˻˻˻ ιιιι ʼʼʼʼʼʼʼʼ 3                               n˻˻˻˻ ιιι ʼʼʼʼʼʼʼʼ˻( p8^7^]]]]]RS232 2 R L     E    A     D c3 3 3 3 3 _PNNPNNSL˻̹J 22̹λ              μ λ 1 2 3 4 5 6 7 8 9 10 11 12 13 μ λF  λ 14 15 16 17 18 19 20 21 22 23 24 25 μ λB λ             μ @c            "        "    "      ` P A RS-232 serial interface, uses the DB25 connector and is commonly used with PC's and modems. The minimum and maximum voltages, names and number of pins were agreed upon several years ago. Some computers have a newer 9 pin connector, (DB9) and other interfaces and connectors are also in use. P Although all 25 pins are not always used in communications, a listing of each pin's assignment is provided on the next screen. S  p]]}]<];]:]9]RS232 3 R L     E    A     D .Q     %                                             #                               $Q˻̹J 23L˻̹J 23̹λ              μ λ 1 2 3 4 5 6 7 8 9 10 11 12 13 μ λF  λ 14 15 16 17 18 19 20 21 22 23 24 25 μ λB λ             μ @  R S - 2 3 2 - P I N A S S I G N M E N T S(%ĿPin 1 PG Protective Ground Pin 14 STD Secondary TD Pin 2 TD Transmitted Data Pin 15 TC DCE Source Transmit TimingPin 3 RD Received Data Pin 16 SRD Secondary Received Data Pin 4 RTS Request to Send Pin 17 RC DCE Source Receiver TimingPin 5 CTS Clear to Send Pin 18 Unassigned Pin 6 DSR Data Set Ready Pin 19 SRS Secondary Request to Send Pin 7 SG Signal Ground Pin 20 DTR Data Terminal Ready Pin 8 CD Received Line Signal Detect Pin 21 SQD Signal Quality Detector Pin 9 (Reserved Data Set Test) Pin 22 RI Ring Indicator Pin 10 (Reserved Data Set Test) Pin 23 DRS DTE/DCE Source DSRate SelPin 11 Unassigned Pin 24 XTC DTE Source TransmitTimingPin 12 SCD Secondary CD Pin 25 Unassigned Pin 13 SCS Secondary CTS $ (% (Reserve p8]7]\\\\Terminal Emulatom^^=^?0 24i 0 24 Modem Software< M  Modems require a "terminal" to operate. A PC can act as a  terminal by using "terminal emulator" software. There are two kinds of terminal programs for PCs, Smart Terminals and Dumb Terminals.d A Smart Terminal program offers many features such as file  transfer (uploading/downloading), screen capture, screen replay,   full screen editing,phone directory and more. Z A Dumb Terminal program offers only basic communications and  has many of the limitations found in hardware terminals in use today. Z Some of the popular terminal/modem software of today: Z Telix, Procomm, Qmodem, Boyan, GT Powercomm, PC Talk (Public  domain). Smartcomm I, Carbon Copy, Bitcomm and Xtalk (Commercial). R You may find it helpful to try several PD modem programs before  deciding on which one to adapt as your own. P ]inal" to ope p\\\\\\error correct k11:1<e  25 Error Correctionv J J Every modem, like every hard disk, has a specified error rate. These rates are so minimal at speeds of 1200 bbs and under, there is no  cause for concern. At higher speeds, the possibility of errors increases as modems become more vulnerable to variations in phone line quality. P Error correction schemes have been devised to ensure that faster modems transmit with 100% accuracy. A better description of error  correction in a modem would be "error detection and retransmission."   How it works is fairly simple. The sending modem performs a  mathematical calculation, known as a CRC check, on a block of  transmitted data. When the modem transmits the data, the modem will  include the result of this calculation with the transmitted data.   At the other end, the receiving modem will perform that same calculation  on the received data. If the results don't match, the receiving modem  will direct the sending modem to retransmit the data. This process  takes place very quickly and is transparent to the user. K R , like every h p\\8\1\0\/\error correct 2 P4> NpQ0NNNNNQ Is it Sometj Is it Something you Need? 26 F Error correction is essential for applications requiring 100% accurate data transmission. A misplaced decimal point or a few incorrect digits can be deadly in banking, accounting, or other financial transactions. Attorneys, physicians, and other professionals using costly data bases need assurance that the information they receive is accurate. Error free transmission is also crucial for remote-site data entry. In general, anyone making extensive use of a  modem to transfer large amounts of data will benefit from error correction. It should be pointed out that most PC users are using software-based error correction successfully.! F  P File TransferTimes in Minutes- Using Different Protocols  Protocol Effic.% 300 1200 2400 9600 MNP-4 (120% throughput)Nͻ--10 Byte File (10K)-- Time to Transmit at:(Typical Utility Files)Xmodem 78 7.1 1.8 0.9 0.2Xmodem/CRC 79 7.0 1.8 0.9 0.2Xmodem/1K 87 6.4 1.6 0.8 0.2Ymodem 90 6.2 1.5 0.8 0.2 Zmodem 95 5.8 1.5 0.7 0.2 Nͼ 100% p.\-\[[[[stats Y>NpQ1NNNNNR1NNNNNR NNNNNQleP File TransferTimes in Minutes- Using Different Protocols 27 Protocol Effic.% 300 1200 2400 9600 MNP-4 (120% throughput)Nͻ--65536-- Byte File (66K)-- Time to Transmit at: (Utilities & Applications) Xmodem 78 46.7 11.7 5.8 1.2Xmodem/CRC 79 46.1 11.5 5.8 1.2Xmodem/1K 87 41.8 10.5 5.2 1.1Ymodem 90 40.5 10.1 5.1 1.1Zmodem 95 38.3 9.6 4.8 1.0N͹--250 Byte File (250K)-- Time to Transmit at: (Applications & Graphics)Xmodem 78 178.1 44.5 22.3 4.6Xmodem/CRC 79 175.8 44.0 22.0 4.6Xmodem/1K 87 159.6 39.9 20.0 4.2Ymodem 90 154.3 38.6 19.3 4.0Zmodem 95 146.2 36.5 18.3 3.8N͹--50 Byte File (500K)-- Time to Transmit at: (Telix & Qmodem) Xmodem 78 356.1 89.0 44.5 9.3 MNP-4 (120% throughput)Xmodem/CRC 79 351.6 87.9 44.0 9.2Xmodem/1K 87 319.3 79.8 39.9 8.3Ymodem 90 308.6 77.2 38.6 8.0Zmodem 95 292.4 73.1 36.5 7.6Nͼput) p[ [t[q[p[o[error correct 3  <D 28 P D 28 What are the Limitations of Software-based Error Correction?_ There are a number of well-known software-based file transfer protocols such as Crosstalk, Kermit, and Xmodem. While these protocols will work in certain applications, this approach also has built-in drawbacks. First of all, software-based file transfer protocols are designed to operate in block mode; that is, to send a complete file from one computer to another. They won't work in interactive situations where you are keying in information at your PC. 6 O For instance, you usually can't use software-based file transfer protocols to work with commercial data bases such as Dow Jones to request stock quotes. There are other serious drawbacks as well: software-based file transfer protocols require compatible software and often hardware - at both ends of the link - and they cannot be used with terminals. Finally, because of the overhead that the software adds, this type of error correction is inherently slow and inefficient. Your throughput may be reduced by as much as 50%. With a 2400 bps modem you may only be trans- mitting data at an effective rate of 1200 bps.n P PP -base pn[!m[[[ZZcom tut 1 l9municP Communications Primer29R In the vernacular of the communications industry, there are a few con-  cepts that need to be understood before the user can understand how a  modem or bulletin board works. For example, take the word BAUD. People  refer to baud and bps as if they were the same, when they are completely  different. A 2400 baud modem operates at 2400 bps which is actually 600  baud! (See Understanding 9600 Baud.)%  O When two machines try to communicate with each other, a couple of things  must be done by both. They must both be set to send and receive at the  same baud rates, for example. Today the most often used baud rate is 2400  baud. That means 2400 bits per second, as said previously. Well, most  users have no idea what bits are involved in a file transfer or a message  transfer. Let's look at another standard word: BYTE. A byte contains 8 bits of information. Within this set of 8 bits are 256 possible permutations. Each letter in the alphabet and each digit and special  special character is represented by a fixed pattern of those 8 bits. A capital 'J' has a different pattern than a lower case 'j,' for example.  It's easy to see that no more than 128 of the total possible patterns would be necessary to represent any text. Thus, we have another 128 that  may be used for 'special purposes.'+ N N  vernacular ' pZ"ZZZZZcom tut 2 9 J30P J30 What, for example? We'll get to that. ' N The sending of bits (on or off, high or low) is, by definition, a binary  process. Computers need only recognize one of two states. The telephone, on the other hand, carries information that is other than binary. It can faithfully represent variations of tones, pitch, and volume. This is called analog rather than binary. The main purpose of a modem is to translate binary signals into analog and vice versa. When sending a set of bits across a telephone, those binary 'states' will have to be converted  into some form of sound (which is, after all, what the tele- phone is designed to best carry). Modulating a signal from binary to analog is the 'Mod' in Modem. Demodulating an analog signal back into binary is the  reverse and is the 'Dem" in Modem.~ We must do more than simply send the binary information (modulated), if  we are to achieve a highly reliable transmission. We have all heard  'noise' on a telephone line. Without doing more than demodulating into  bits, the receiving modem will no doubt have a nearly impossible time  distinguishing between sounds and noise. Perfect transmissions are not  always necessary. Examples include the transmission of plain text files.  Recall that all that was necessary to send any letter, special symbols, or digit was a capability that required no more than 128 different combinationsSt.  pZ#ZZZZZcom tut 3 9 J31P J31 of bits. 7 bits are sufficient to represent 128 permutations of a char- acter. That is, if a byte were only 7 bits long then it could contain as many as 128 different sets of bits being on or off. However, a byte is  8 bits long by definition. So, in what is called ASCII (American Standard  Code for Information Interchange) transmissions we can use the first 7 of  those bits to represent data and the 8th bit to represent some form of insurance or integrity check..  N This is called using 'PARITY'. You can establish a convention between the  sender and the receiver so that every byte will have an even number of  bits (or odd) and use the 8th bit to adjust the count. If the receiving  end ever gets a byte that has "wrong" parity, then it knows it received a  "garbled" byte. That is all there is to parity checking in an ASCII transmission. Not perfect, but sufficient for most text.  N Program files or data files that have been compressed (ARCHIVED) use all 8  bits in every byte to represent information. So, we have lost the ability  to use parity as an integrity check. Instead, in every protocol other  than ASCII we add either one or two full bytes to the end of a 'block'  of bytes. The block is a fixed length (usually 128 bytes). The purpose  of those one or two bytes is to contain what is called a Cyclic Redundancy Check (CRC). Like parity, the CRC is constructed at the sending end Qto repre pZ$ZYYYYcom tut 4 D-2P I 32 to create a pattern of bits that demonstrates that the preceding entire  block of bytes has been received with integrity. The Receiving end dynamically creates its own CRC from the information received and compares  it to the byte or bytes received at the end of a block. If it doesn't  match then the block must be rebroadcast (requested by sending to the  sender a signal that says: "Negative Acknowledge" - NAK. If it was ok, then it sends an ACK - meaning "Acknowledge", and the next block is sent.  K  Now, let's go back to the idea of baud. At 1200 baud, the modems are able to send and receive 1,200 bits per second. How many bits per byte? Yes,  8, but not on a telephone line if you are using modems! Instead, we  bracket a byte by sending what is called a start bit before the 8 bits of  data and ending with what we call a stop bit (sometimes 2 - at 300 baud).  So, every byte requires at least 10 bits. Thus, at 1200 baud, your  maximum possible data transfer rate is 120 characters (bytes) per second!  K  Now we know what to send, how many bits are required, and the existence of  the ACK/NAK response from the receiver. So, why don't we get 120 bytes  per second transfer rates when using 1200 baud modems? Well, we already  saw that for every 128 bytes of data, in most protocols, we send an  additional one or two bytes of CRC. We do not count the CRC byte(s) as data! Yet they take time to transmit. Also, it takes time for most Wmons pY%Y'Y$Y#Y"Ycom tut 5 9 J33pP J33protocols to react to the ACK or NAK. For example, assuming all is well,  the sender has a few hundred blocks to upload to the receiver. After the  first block is sent, he must wait for the receiver to analyze the CRC and  decide if it is going to respond with the ACK or a NAK. Then it takes a  moment to respond to the sender who, in turn, has to receive it, verify  that it got here properly and decide whether to send the next block or to  resend the last one. That takes time. All time used as described above  is called 'overhead'. Overhead does not include the transmission of DATA,  only control information and time. Thus, it is impossible to get an  effective data transmission rate of even 118 characters per second, let  alone 120. But, we know that the telephone is capable of carrying sound  in both directions simultaneously. So, why should the sender have to  wait for the receivers ACK or NAK? This mode of operation is often  called HALF DUPLEX.3  O The answer, of course, is that it does so only by convention. Newer  protocols do not wait. They assume that a transmission will be success-  ful and will result in getting an ACK. So they go immediately to the task  of sending the next block, always listening, of course, for the ACK or  NAK. When an ACK is received, all is well and we have gained perform-  ance. If not, the software has to decide which block or blocks have to be rebroadcast. In order to do that it should be obvious that the ACK or U For  p!Y& YXXXXcom tut 6 I 34P I 34 I  NAK is not simply a single byte. Rather, it includes a byte that is  called the packet number (0 to 255), and possibly more information. If  an ACK is received, the recipient knows which blocks (packets) it is  describing. Similarly, it would know with a NAK. Yes, more bits and  more overhead!=  I  Well then, let's review a few more contemporary terms and more practical information. A I  For example, almost nobody uses ASCII transfers anymore. Why should they when they are so poorly controlled and when you realize that only uncom-  pressed raw text can be sent with it? Still, a great many first time communications users try to do so. It is a good test of a new system.  O Error correcting file transfer protocols are the most efficent way to  transfer files with a modem.2R Please refer to the section: "Parameters and Protocol" for detailed information on all of the popular protocols. yt pX'XXXXXfeatures 1 e' v@35RP @35R  Introduction to Communications Programs N Today's communications programs for PCs are full featured, running the PC/MS-DOS operating system, that is able to meet the needs of almost any  user. Features to look for include:* N - An extensive range of built-in file transfer protocols,  including Zmodem, CompuServe Quick B, Xmodem, Xmodem-1k, Xmodem-1k-g,  Ymodem (TRUE), Ymodem-g, Kermit, SEAlink, Telink, Modem7, and ASCII.  Use of several 'external' protocols to be defined and called.  In this way, almost any kind of file transfer is possible.  N - Powerful multiple dialing directories, holding hundreds of entries  each. An entry contains many pieces of information required for  communicating with remote services, such as the phone number and  communications parameters. - Automatic queue redialing for hard-to-reach numbers. P - DEC VT102 and VT52 terminal emulation. Keys may be redefined by the  user.ms N & p~X(}XXXTXSXRXfeatures 2    36 N 36 N N - Extensive script language which allows automated logons and many  more complicated functions. / N - Full access to DOS including a DOS shell, a DOS command option, and  full path support.9 N - A Host Mode with file transfers, operator paging, a remote DOS shell,  and two access levels.5 N - A chat mode, keyboard macros, a scroll-back buffer, session capture,  usage log, translate table, and a variety of other features. 1lows automat pQX)PXwwwwparms 1 G  6 Co37 Communications Parametersm There are a number of parameters that can be changed. The baud rate is  the speed that you are are using to communicate. (It should really be  called bps rate). 1200 baud and 2400 baud are the two most common   speeds in use, and represent about 120 and 240 characters per second,  respectively.> S The highest baud rate both the dial and answer modems can support will  usually be your baud rate. For null-modem, direct connection AT's support baud rates all the way up  to 115200, however a fast PC is needed for the higher rates (a stock 4.77  MHz XT can handle 9600 and possibly 19200 baud, higher rates need an AT  class computer). Parity is a form of error checking. Allowable parities are None, Even,  and Odd. Data bits are the number of bits in each character. Allowable values are  7 and 8. Finally, the number of stop bit parameters can be set to either 1 or 2. The most common format for BBS use is a baud rate of 1200 or 2400, U% pw*wwwwwparms 2 X A9M38R 8 da38R 8 data bits, no parity, and 1 stop bit (1200,N,8,1). On many large networks such as CompuServe, the data format used is 1200,E,7,1.g The communications parameters also allow you to select the communica- tions port you want to use.  FILE TRANSFERSs G Sending files from one computer to another is one of the most useful things you can do with your modem. Your terminal program should support  a full assortment of the most popular file transfer protocols, including  Xmodem, Xmodem-1k, Xmodem-1k-g, Zmodem, CompuServe Quick B, Kermit, Ymodem, Ymodem-g, SEAlink, Telink, Modem7, and ASCII. Today file trans- fers are very fast, most forms of file transfers use a buffer, and full  error detection. Good terminal programs allow you to define up to four external protocols,  which are completely integrated into the file transfer menus.  pw+wdwaw`w_wparms 4   Dow39 Downloading (Receiving) Files To start downloading (receiving) a file from a remote host, you must usually inform the remote host of the files that you want it to send to  you. You must then tell the host to start and put your system into receive. If you have selected Xmodem, Xmodem-1k, Xmodem-1k-g, or ASCII, as the  protocol, your program will ask you for the filename to save the file to.  Some terminal programs watch what you type while online, and will often  know the name of the file you want to transfer. In the ENTER case this  name will be displayed and all you have to do to accept it is press Return. To confirm your choice or give another filename. If you select any other  protocol, the remote sender of the file will supply the name to save the  file to.F N Your program may also have a "default" download directory which will be  used if you don't specify the target directory.  N O do p^w,]w w wwwparms 5 c) Dow40R Downloading (Receiving) Files- Continued dDuring the transfer, a full status window is usually displayed showing the elapsed time, the number of bytes received, and an approximate Char-acter Per Second rating, which can give an idea of the effective speed of  the transfer. Batch protocols will also display the expected file size and file transfer time. ASCII transfers may not have a status window.  Transfer can be canceled at any time by pressing the ESCAPE key. N N Uploading (Sending) Files  N To start uploading (sending) a file to a remote host you must also usual- ly inform the host of the file you will be sending it. To start the upload on your end choose the transfer protocol you want to use to send the file. After you have selected the protocol, you will be asked for the file(s) to send. You may be able to use the wildcard characters ? and * (see your DOS manual, for more information about wildcard charac- ters). During the file transfer, a full status window is usually dis- played, unless you are using ASCII protocol. d  pw-wvvvvparms 6 mp>il41R File Transfer Protocolsn Xmodem - This is the most popular protocol in use today, but it is slowly being replaced by quicker and more reliable protocols. Xmodem  sends files in blocks of 128 characters at a time. When the receiving  computer is satisfied that the block has arrived intact, it signals so  and waits for the next block. Error checking a checksum or maybe a more  sophisticated Cyclic Redundancy Check. Your program should support both  and switch as necessary. The Xmodem protocol also needs a setup of no parity, 8 data bits, and 1  stop bit. If your communications parameters are different from these  when you start an Xmodem transfer, some programs autoswitch to the re- quired setup for the transfer, and back to the original setup after it  is finished. Another useful option is Relaxed Xmodem timing. This is  for use with remote services that can not tolerate strict timing during  Xmodem transfers. pv.vKvFvEvDvparms 7 R AE KS{D$dem-1kP Xmodem-1k - This is a small variation of the above that uses blocks 42 that are 1 Kilobyte (1024 bytes) in size. This protocol is still mistak- enly called 'Ymodem' by many programs, but people are gradually moving  over to the proper name. Xmodem-1k-g - This is a variation of the above that is meant for error-free channels such as error correcting modems or null modem cable  links between two computers. It achieves great speed by sending blocks  one after another without waiting for acknowledgement from the receiver.  Because of this however, it can not resend blocks in case of errors (and  thus the need for an error-free link). If an error is detected by the  receiver, the transfer is aborted. This protocol is still mistakenly  called 'Ymodem-g' by many programs, but people are gradually moving over  to the proper name. CompuServe Quick B - This protocol is used only on the CompuServe Information Service. It is quite fast and specially suited for the net- works used in accessing CIS, which have large turnaround delays. This is  a windowed protocol, which basically means that unless errors are detect- ed, data is being sent at all times. A CIS Quick B transfer is totally  controlled by CompuServe. After telling CIS what file(s) to send, the  user does nothing. Some programs, in terminal mode, detect the command  from CIS which tells it to start the transfer. p pCv/Bvuuuuparms 8 RDax -P Zmodem - This advanced protocol is very fast and incredibly reliable, 43 and offers many features. Zmodem can transfer a group of files in one  batch, and keeps the exact file sizes and dates. Zmodem can detect and  recover from errors quickly, and can resume an interrupted transfer at a  later time (this feature, called Crash Recovery, may be toggled in the  'Protocol options' page of the Configuration Menu). Zmodem is also very  well suited for satellite links and packet switched networks.a SEAlink - SEAlink is an advanced version of Xmodem developed by System  Enhancement Associates. It is a sliding window protocol SEAlink is 15  to 25 percent faster than regular Xmodem. SEAlink passes a file's name,  size, and date when transferring it, and can be used to send more than  one file at a time. ASCII - in an ASCII transfer, it is as if the sender is actually typing  the characters and the receiver is just recording them. There is no form  of error detection used. Usually only ASCII files can be sent in this  way, as binary files contain characters which would foul-up the screen.W Ymodem - This protocol is a variation on Xmodem, which allows for multiple files to be sent per transfer. While transferring files, it  keeps the correct name, size, and date, and may use 128 or 1024 byte block sizes.ibly rel pu0u|uxuwuvuparms 9 sTd44 Ymodem-g - This protocol is a variation on the above, which achieves  very high transfer rates by sending blocks one after another without waiting for acknowledgement. This, however, means than an error-free link  such as an error-correcting modem or null modem cable between two comput- ers is needed. If an error is detected by the receiver, the transfer is  aborted. Telink - This protocol is mainly found on Fido BBS systems. It is basically the Xmodem protocol using CRC checking with an extra block sent  ahead of the file telling its name, size, and date. This protocol allows  more than one file to be sent at a time.v Modem7 - Modem7 is a close cousin to Xmodem that passes the filename  before starting the transfer, thus taking away some of the user's work.  It is common on CP/M systems. This protocol allows more than one file to  be sent at a time. Kermit - The Kermit protocol was developed to make it easier for   computers of different types to send files to each other. Almost any  computer using Kermit can be set up to send files to another computer  using Kermit (the same can be said of Zmodem however). ve, whic puu1tu.u+u*u)uparms 10 pR Whi45R Which One to User Your program will probably support several built in file transfer proto- cols and possibly some external protocols. It can get confusing to decide which one to use. When both sides of the connection only support  one protocol, then obviously that is the one to use, no matter what its  deficiencies. Otherwise some protocols are a better choice than others.  On CompuServe, CIS Quick B should be used. For most purposes, Zmodem is  the best all around protocol. It is very fast and very reliable. Ymo- dem-g and Xmodem-1k-g are slightly faster. However these two protocols  need an error-free link. After that, Ymodem, SEAlink, and Xmodem-1k are  quite fast and pretty reliable. The last choice would be Xmodem and its  close cousins Telink and Modem7. Avoid ASCII transfers which are suitable only for text files transfers and do not perform any error detection or  correction. bab p(u2'uttttUNDR 9600 1 OK&0 ~OOOOOOOOOOOOO46 Understanding 9600 Baud Communications M Not long ago, many data communicators thought that dial-up modem manufacturers had pushed transmission speeds to the limit with the introduction of 2400 bit per second (bps) modems. It was widely believed that a "dedicated" phone line would be necessary for any "faster" transmission. Recently, however, several manufacturers have creatively combined relatively mature techniques of data transmission with newer technology and have introduced 9600 bps modems that use regular phone lines!J N Each time we experience advances in technology, we soon develop a  "wish list" of features we would also like to have. For instance, some Apple Macintosh owners would like to run IBM compatible software and HP Laserjet  owners sometimes want to use "Postscript". It seems that 9600 bps users  are simply looking for as many modems as possible that are "compatible with  one another".?  N The key point here is "compatible with one another" not "Hayes compat- ible". Most of us realize there are widely accepted standards for 300, 1200 and 2400 bps modem transmissions but not for 9600 bps. thought that$ pt3tttt~tu96 2 MR Unf47R Unfortunately, a widely accepted standard for full duplex 9600 bps transmission as defined by the International Consultative Committee for Telegraphy and Telephony (CCITT) does not yet exist (the CCITT is currently considering proposals for a new 9600 bps dial-up standard). This means  that today's 9600 bps modems do not offer cross-manufacturer compatibility. The CCITT HAS endorsed a half duplex and a full duplex 9600 bps standard, but to date implementations of these relatively flexible standards have  been proprietary, i.e., even the "standardized" modems from different manufacturers are not compatible., W All this means that modem users who want to enjoy the dream speed of  9600 bps must weigh the pros and cons of each 9600 bps technique before  committing to a particular 9600 bps design. ! rd for p}t4|tttttu96 3 Pj I !& $R THE48R THE ROAD TO 9600! N High speed data communications via the dial-up phone network is limit- ed by the available phone line bandwidth and by random channel impairments. Just as the diameter of a pipe limits its liquid flow capacity, so does the telephone channel bandwidth limit its data flow capacity. N The roughly 30-Hz available in the telephone bandwidth poses few  problems for 300 bps modems, which only use about one fifth of the band- width. A full duplex 1200 bps modem requires about half the available  bandwidth, transmitting simultaneously in both directions at 600 baud and  using phase modulation to signal two data bits per baud. "Baud rate" is  actually a measure of signals per second. Because each signal can repre- sent more than one bit, the baud rate and bps rate of a modem are not  necessarily the same. In the case of 1200 bps modems, their baud rate is  actually 600 (signals per second) and each signal represents two data bits. By multiplying signals per second with the number of bits represented by  each signal one determines the bps rate: 600 signals per second X 2 bits  per signal = 1200 bps.  In moving up to 2400 bps, modem designers decided not to use more Xwork pt5tssssu96 4 pR band49R bandwidth, but to increase speed through a new signaling scheme known as  quadrature amplitude modulation (QAM).( N In QAM, each signal represents four data bits. Both 1200 bps and 2400 bps modems use the same 600 baud rate, but each 1200 bps signal carries two data bits, while each 2400 bps signal carries four data bits: 600 signals  per second X 4 bits per signal = 2400 bps. " N A technique known as adaptive equalization enables 2400 bps modems to  adapt to phone line impairments call-by-call. Essentially, if the modem is experiencing problems with a noisy line, it looks for a "sweet spot" in the bandwidth and attempts to avoid troublesome frequencies. This technique  makes 2400 bps modems more tolerant of line noise than their 1200 bps  counterparts that use compromise equalization (a one-size-fits-all approach). M While these advanced modulation and equalization techniques in 2400  bps modems provide for double the data rate of 1200 bps modems, they also  result in a design at least four times more complex than 1200 bps modems. P Which brings us to the problem of designing a 9600 bps modem.  ps6s\sYsXsWsu96 5 f   P J50R Jumping to 9600 from 2400 bps is several orders of magnitude more  complicated than going to 2400 from 1200 bps. Telephone network character- istics make it highly unlikely that success will be had in extending the "data signal alphabet" (number of bits represented by each signal) beyond four bits per signal.; N Instead, modem designers must increase the bandwidth that is to carry  the signal. This presents a very big problem. In fact, at speeds of 4800  bps (1200 signals per second), the transmit and receive channels must be expanded to the point where they actually begin to overlap. A 9600 bps "band" requires roughly 90 percent of the available bandwidth, making it impossible to have two-way communication without the bands interfering with each other.E N A helpful analogy to the problem might be a two lane highway: traffic must flow in both directions simultaneously, but to carry more  cars per unit of time, highway designers must either increase the number  of lanes in each direction or widen the two lanes to accommodate driver  error with a margin of safety. Unfortunately, these options are not available to modem designers as the available bandwidth is of a fixed size.S Ql pVs7Usrrrru96 6 % Wit51R With these considerations and limitations in mind, let's examine three  basic ways to accomplish full duplex (two-way) 9600 bps communications:  echo cancellation, virtual full duplex (achieved by half duplex systems), and asymmetrical frequency division., N ECHO-CANCELLATION N This method solves the problem of overlapping transmit and receive  channels. Each modem's receiver must try to filter out the echo of its own transmitter and concentrate on the other modem's transmit signal. This presents a tremendous computational problem that significantly increases the complexity - and cost - of the modem. But it offers what other schemes don't: simultaneous two-way transmission of data at 9600 bps.g The CCITT "V.32" recommendation for 9600 bps modems includes echo- cancellation. The transmit and receive bands overlap almost completely,  each occupying 90 percent of the available bandwidth. Measured by computations per second and bits of resolution, a V.32 modem is roughly 64 times more complex than a 2400 bps modem. This translates directly into added development and production costs which means that it will be some  time before V.32 modems can compete in the high-volume modem market.Z   pr8rrrrru96 7 a D 52 Despite the fact that V.32 is a recognized standard, it is  uneconomical and unnecessarily complex for personal computer applications that don't require simultaneous two-way 9600 bps transmission._  HALF DUPLEX SYSTEMS  (Virtual Full Duplex) N Half duplex solutions devote the entire bandwidth to 9600 bps in one  direction at a time, and "ping-pong" the data flow back and forth to simu- late full duplex. This is potentially the simplest scheme. Its perform- ance is acceptable in data transfer applications that don't involve user interaction, i.e. file transfers. Even so, advanced error-control protocols that require ACKnowledgments to be sent in response to received data blocks generate a high number of "line reversals" which greatly impair overall  data throughput. In short, the benefit of higher speed is so significantly compromised by line reversals in half duplex sessions that the net gain in data throughput may be marginal at best.| If users want to operate in an interactive mode, their data must be sent to the remote computer, the data channel must be reversed, and then the data must be echoed back. This process results in significant turn-around delays which can be very frustrating to users.v   pr9r8r5r4r3ru96 8 953R Hal53R Half duplex modems of this kind are most often based on CCITT recom- mendation, V.29 for half duplex 9600 bps transmission on the dial-up net- work. V.29 based data pumps used in facsimile systems are available as LSI chip sets, providing a short-cut to modem manufacturers, particularly to companies that don't develop their own modem technologies. But the major problem is that the V.29 modulation scheme has been outdated by the fact  that it operates in a half duplex mode and doesn't provide good signal to noise performance. The V.32 recommendation, which operates in a full duplex mode and employs Trellis Coding Modulation offers greater throughput and a greater immunity to channel impairments.| Modems employing V.29-based modulation include products from Racal-  Vadic, Comspec, Develcon, Gamma Technology, Microcomm, and Electronic Vaults, Inc. (EVI). These modems, however, are NOT mutually signal compatible - cross-manufacturer compatibility does not exist. N  Another modem in the half duplex category, but not based on V.29 modulation, is the Telebit Trailblazer (R), which uses a proprietary modu- lation method. O Pt ofte p2r:1rqqqqu96 9 9 K54R O K54R Trailblazer is based on a multi-carrier technique. Conceptually, the  transmission channel is divided into many (512), independent, very narrow  channels (think of our two-lane highway and imagine it as having 512 very  narrow lanes going in one direction and you've got a fair idea of how  Trailblazer divides the bandwidth). The main advantage is that no receiver adaptive equalizer is needed because each channel is very narrow compared  to the overall channel bandwidth.+ N Further, in the Trailblazer modulation scheme, the modulation rate in  each narrow channel can be changed somewhat independently. Trailblazer is  different from many other modems in that the decision to fall back to lower speeds is built into the modem protocol, rather than controlled by the  user's computer port. It is claimed that in the face of channel impair- ments, throughput can be adapted gracefully to channel conditions. Tradi- tional modulation systems would have to fall back in larger steps. But  there are three inherent MAJOR problems:' O 1. The turn-around delay is very long compared to conventional modulation techniques because data must be sent in large blocks. A typed  character may take several seconds to be echoed back to the system that  O Plti-carrier  pq;quqrqqqpqu96 10 9 K55 O K55 sent it. As a result, the system fails to achieve the illusion of full  duplex and is not really suited to interactive online sessions. O 2. The Trailblazer receiver cannot "track" carrier "phase jitter"  (phase jitter can be thought of in terms of "phase shift": think of how the whine of a race car goes from higher to lower as it passes the viewer -  the frequency of the sound is said to be "shifted" or "jittered"). Instead of canceling out phase jitter (which is commonly encountered on long dis- tance calls) the Trailblazer can only respond by lowering throughput to  gain more immunity to phase jitter.+ N 3. The ability to transmit at the maximum rate when subject to channel impairment is considerably less than for conventional modems. There is one notable exception: the multiple channel technique offers  extremely good immunity to impulse noise because the impulse energy is  distributed over narrow channels. While conventional modems can achieve  similar results through special coding or filtering techniques, they rarely implement such methods.7  poq<nqqqqqu96 11  ASY56 ASYMMETRICAL FREQUENCY DIVISION N When one considers the nature of most PC datacomm applications, it is  realized that most applications are interactive. One end is using manual (typed) data entry and the other end data file transmission.  O Few, if any, PC users can justify using an expensive 9600 bps channel  to carry their typed characters when they realize that 300 bps translates  to 360 words per minute. Assuming one could type 100 words per minute,  even a 100 bps transmission channel would be sufficient.  N On the other hand, file transfer should take advantage of the tremen- dous speed of the microprocessor. Serial ports are often set at data rates in excess of 19,0 bps. 4 N Considering these inherent characteristics, a communications scheme  incorporating a high speed and a low speed channel would be best suited  for most PC datacomm applications., O Remembering the highway analogy (higher speeds mean wider lanes), one  can see how such a method would grant modem designers a large portion of e pq=qppppu96 12 957S the a57S the available bandwidth for a 9600 bps channel and still leave enough room  to accommodate a narrow 300 bps channel without any channel overlap.[ By utilizing two discrete channels, such a modem would avoid costly,  complex echo-cancellation schemes. Because the channels carry data in both  directions simultaneously, the communications link is a true full duplex  connection. This means that data entered at one system would be almost  instantaneously echoed back - eliminating the frustrating turn-around delay experienced in half duplex sessions." N USRobotics has developed just such a modem. It passes data in one  direction using the V.32 modulation technique (a very robust method that is very immune to phone line impairments) but employs only a 300 bps channel  in the opposite direction so that the channels do not overlap and echo- cancellation is not necessary. . N The use of the high-speed channel by the two modems is based on data  demand. In most applications, however, "channel swapping" will not be  required. For interface elegance, the modems employ a 4K buffer that allows P O Pbps channel  pp>pipfpepdpu96 13 958 them58 them to perform data rate conversion: sending and receiving speeds remain  constant between the modem and the computer - it is only in between the  modems that transmitted and received data run at different speeds. [ For interactive sessions, users are assigned the low-speed channel  while the data is sent to them (long mail messages, menus, files, etc.) in  the 9600 bps channel. 7 N For file transfer sessions, the data blocks that make up a file are  sent in the 9600 bps channel while the corresponding ACKnowledgments are  returned in the 300 bps channel. An asymmetric frequency division scheme  is ideal for file transfer where large data blocks (usually several hundred bytes in length) are transmitted in the high-speed channel and the ACKs  (usually only a few bytes in length) are carried in the low-speed channel. N If a user switches from an interactive mode to file transfer and then  back to interactive mode, the high speed channel is dynamically and auto- matically assigned to the system with the greatest data demand.  sending pcp?bpoooou96 14 n9A B 2 A BRIEF COMPARISON59R Three options exist for data communicators who desire to operate at  9600 bps:E N 1. V.32-type modems offer a full duplex connection but do so by  virtue of echo-cancellation. This technique is so complex, and has proven  so difficult to employ, that the cost for such modems will remain prohibi- tively high and their implementation a delicate task for some time to come. N 2. Half duplex modems (either V.29 or multi-carrier) offer 9600 bps  but the turn-around delay inherent in half duplex links severely compromise overall throughput. This degradation of throughput, however, can be more  than offset by data compression techniques assuming the modems in question  support identical compression protocols and are operating on relatively "clean" phone lines. Both half duplex methods suffer disproportionate  degradation on "noisy" lines: the V.29 modems must spend more and more time in line reversals as detected data errors increase, and the multi-carrier  modems must sacrifice throughput to gain noise immunity. N 3. Asymmetrical Frequency Division offers 9600 bps communications in  a true full duplex implementation. By efficiently utilizing the available  bandwidth, these modems provide users with high speed file transfer capa-V options ex po@ooooou96 15 F R bili60R bilities and fast response in interactive sessions. Because the transmit  and receive data channels do not overlap, expensive echo-cancelling tech-  niques are unnecessary making these modems economically efficient.] For interactive sessions, users are assigned the low-speed channel  while the data sent to them uses (long mail messages, menus, files, etc.)  9600 bps channel. N! IN CONCLUSION" N Until a widely recognized standard is agreed upon by the standards  community, and implemented by several manufacturers, modem buyers must  weigh the benefits and detriments of each 9600 bps scheme. N V.32 would be best where symmetrical, full duplex, synchronous commu- nication is desired (for example, dial-up HDLC links between multiplexers)  and where the user can modify his software to accommodate non-"AT" command-driven modems.*ive sess poAo[oXoWoVou96 16 961 Q 61 Q V.29 modems would be likely solutions where absolute lowest price is  required and conformance to an international standard (in a very limited  sense) is desired. Multi-carrier transmission schemes are well-suited to applications  that require maximum one-way throughput and where circuit conditions are  known to be good. This transmission method is also ideally suited for  circuits where immunity to impulse noise is paramount.  N Users who most often work with one-way file transfers (PC-to-PC) or  with real-time applications may opt for an Asymmetrical Frequency Division  scheme, which is suited equally well for either application. The elegant  approach to the frequency division (avoiding overlapping bandwidths) also  allows these modems to present a very economical ratio between dollars and  bps.J N Potential high-speed-modem buyers should also consider the aspects of  ease-of-use, ease-of-implementation, and downward compatibility with existing implemented standards (the CCITT's V.22 bis for 2400 bps, Bell  212A for 1200 bps, and Bell 103 for 300 bps). whe pUoBTonnnnu96 17 r 9T SCRQ! POST SCRIPT62 N Many modem users have voiced confusion and consternation about the  lack of compatibility between modem manufacturers at speeds greater than  2400 bps. C N Modem manufacturers have embraced the Bell 212A and 103 standards for  1200 and 300 bps. In these post-divestiture days, however, Bell no longer  sets modem standards in the U.S. and hence, U.S. modem manufacturers have  turned to the CCITT as a definitive source for standards. The industry- wide acceptance of the CCITT's V.22 bis standard for 2400 bps is the best  example of this shift.8 N The CCITT recommendations V.29 and V.32 for 9600 bps have not resulted in compatible implementations. It is important to remember that V.29 was  originally developed as a four-wire full duplex leased-line modem and has  since been adapted by various manufacturers to encompass half duplex dial  up applications. Other problems with V.29 are that it compromises trans- mission speed and is poor for interactive sessions. V.32 is proving to be  prohibitively complex and exceptionally difficult to implement (driving  development and production costs up). $ have v pnCnnnnnu96 18 963/ q63/ q Recognizing the need for an alternative to the V.32 recommendation,  the CCITT has requested proposals from modem manufacturers. N Presently, two proposals are being considered by the CCITT. One is  the multi-carrier scheme developed and sponsored by Telebit. The other is  an Asymmetrical Frequency Division scheme developed and sponsored by USRo- botics.G P lternativ pnDnznwnuntnsysop 1 k9Kind P Be Kind To Your "Sysop"64 These guys & gals are letting us use their computers, their time, and  their money so we can possibly get some enjoyment out of it. Unfortunate-  ly, many users are abusing the privilege (and therefore the sysops!) Don't be an abuser!8 S You may find you can't upload to the BBS because you don't have any files  that BBS doesn't already have. Leave a note to the sysop and thank them  for the use of the system. Look through the message section (maybe  someone asked a question and YOU know the answer!) REMEMBER that there is  a REAL PERSON at the other end of the line. S Many users still view BBS systems in the same light as a soft drink  machine. If they don't get exactly what they want out of it - instantly,  they start kicking it. User attitudes have caused many BBS systems to go  mail-in validation. Sysops believe that abusers won't go to the trouble  of registering by mail.4 T Courteous PC and BBS users enjoy and appreciate this service and so should  you! That's right, SERVICE. Sysops are providing a useful "free" or "almost free" service!s# psnErn3n0n/n.nsysop 2 R2When s65TWhen sysops do request payment for the use of their BBS, charges are  rarely over $25 annually. It is widely accepted that Sysops are inter-  ested in people, not profits. Pay BBSs generally are large boards that  need the financial support to cover the cost of operation.  J Sometimes a user will get the mistaken idea that a sysop is "freeloading".  BBS users sometimes resent paying anything for the service they are using.  Remember, even when a BBS charges a membership or usage fee, the sysop  ends up paying most of the operating costs out of his/her own pocket. M  Just a quick note. Selecting "C"omment on most boards is a quick and painless way to tell sysops you appreciate their efforts! A simple thank  you is a lot more than they are getting now from most users.  N f th p-nF,nmmmmsysop 3 jxDN 66jFrom The Sysop's Perspective Messaging: "Whatever happened to the COMMUNICATIONS in telecommunications? Is this  the result of the Computer Age, that people don't talk or communicate  with each other? Are we getting so totally in tune with our equipment  that we're excluding PEOPLE? If so, then Orwell's predictions are tame  in comparison with reality."- U Some sysops feel this way but we have found that premium BBSs with  hundreds of megabytes of files have very active message sections. A BBS,  like a club, TV program, book or magazine, may be popular or may be a  "dive". Sometimes it is a function of nearby BBSs. UThe breadth of callers can also effect the quality of a BBS. Sysops who "chat" and/or leave messages to users seem to have the best boards. Many sysops of more popular BBSs share the management of their board with the users!E a pmGmmmmmsysop 3a D BHHHHHHHHHM67R N 67R N Hacking:Bͻ ͼB  "Do you have a logon code for this system (Y/N) ==> Y <=="  "What is your account number? 775"  "What is your logon code? PASSWORD"  "INVALID LOGON CODE"-  "Do you have a logon code for this system (Y/N) ==> Y <=="  "What is your account number? 305"  "What is your logon code? PASSWORD"  et cetera, ad infinitum et ad nauseam.  > Hͼ N P "Hackers. Or so they'd like to believe. Vandals, pests, yes. Hackers? They should be so talented, devoted and lucky. Why do these computerized delinquents find such delight in trying to break into bulletin boards?  Don't they realize that sysops are ordinary people trying to find a little  enjoyment in their hobby? Why pick on me? I'm spending a lot of time and   pmHm1m.m-m,msysop 4 h mone 68 money trying to provide people a service for free, and they want to go and  spoil it for everyone. If they want to log onto the system, all they have  to do is apply for a logon. Why make life difficult for everyone? Leave  me alone. Go pick on CompuServe.")  I  Breaking into a BBS is wrong. Don't do it. Ok? If you do try to log on  to a BBS without using your id, don't create a nuisance or cause any damage! When using BBSs, some sysops will allow you to attempt to exceed  your access rights so you can understand the system access level and  security. Satisfy your curiosity. A parallel to BBS security is a  "locked door". You may one day have an urge to see if a door is locked.  It is probably okay to try turning the knob, but don't break the glass at  your local bank to check and see if the alarm works.  PWhat The Sysop Sees:: N A Caller logs on and leaves E-Mail to a friend. Lines only fill half the  screen. He's probably using a Commodore 64. He goes to the file trans-  fer section, and selects UltraTerm protocol, choosing a file that indi-  cates it's a TRS-80 program. BBS goes to send, he figures out that he's  somewhere he doesn't want to be and drops the carrier.  N Pe for f p+mI*mllllsysop 5 9 I 69MP I 69M  Use the (g) goodbye command and log off properly. Today most BBS systems  reset quite easily and have special "event" scheduling to deal with system  "hangs". All sysops would prefer you exit their BBS in an orderly fashion.C  N Another caller logs on four times in a row, but keeps losing the  carrier before he can do anything. He's probably phreaking on a  cheapie phone service. "Phreakers" get caught. Of course, new users sometimes have trouble connecting because their switches are not set  right or their parameters are wrong.'  N Most sysops prefer a public message addressed to ALL, over a private  comment to the sysop. Public messages are often answers to questions from  new users and benefit all. A sysops's mail averages 40 messages a day! K UWhen school's out, BBSs are buzzing. New callers seem to have a sticky CAPS LOCK key. (Everything they type is in uppercase.) These new call- ers seem to dart to the phone listings for other BBS systems. Sometimes they will leave a message for the sysop asking him for advice on pirate  BBSs and software piracy. At least they get to the point. After all, itVnd log plJlllllsysop 6 9 I 70P I 70 N is often said, "if you want something, just ask". I  "What is a file with a "ZIP" extension?" is the most common message left by new callers.  "How do I download a file?" ranks right up there in the message/question competition. New callers can also be identified by their "two finger" typing method.  J  Callers seem to prefer fantasy names for passwords. The only thing more rare than a thank-you message on a BBS is a user changing his/her pass- word.I J  Conference users attract the "letters to the editor" crowd. These folks  specialize in the topic of their choice. They tend to really know their stuff and make their points well. + QAnother caller successfully downloads a file. Sit. Wait. Wait somemore The system eventually times out and drops him. ant someth plKl-l*l)l(lsysop 7 9 J 71P J 71 P Remember when your mother told you "close the door when you leave"? If you only connect to get some "free software" then at least exit the BBS properly.@  O BBS systems now have a special "log-off after transfer complete" option so you can "go to bed" while the file transfer(s) are taking place.   J  Along with all the other goodies that have bitten the dust, there's good  old APPRECIATION. Each BBS fields thousands of calls. Only a small percentage of users seem to express gratitude. Some of us may think BBS privileges are an automatic right. Sorry to disillusion anyone, but that "isn't so." @ O All BBS privileges are controlled by the sysop. The master switch for  the system is within his reach, and he can hit it in a flash. Alterna-  tively, he can ban anyone he wishes from his system. Callers use a BBS at the sysop's discretion. BBS access rights are not granted by the U.S. constitution. It's a sysop-given privilege! N It is clear that sysops don't get all the appreciation they should while  they grant us BBS privileges and benefits. We should respond by creating Utold you "c p'lL&lkkkksysop 8 HPI 72P I 72 I  N a "sysop Appreciation Day"! Now for the moral of the story. These are only the insights of a few  sysops. There are sysops that have these kinds of concerns. Sysops  (especially the best and most devoted ones) may reach a saturation point  and wind up depriving the general public of their services.  I  The day may come and very soon at that, when the high quality BBS's will  be all gone. This is nothing more than a plea for everyone to clean up their acts before it's too late. If nothing else, when you're on a bulletin board, leave a little message to the sysop. "Thanks for the useof your system" or "Fine BBS you have here." Let them know they're appreciated. When I see a message like that, I say to myself, "THAT's why I'm doing all this!" Sysops are real, live human beings with feel- ings and emotions. Let's start treating them as such! y pkMkkkkkaddict 1 g#R THE73R THE TRAGEDY OF AN ON-LINE ADDICTION7by Steve Kingt "Did you know that last month's phone bill is over $450?" my wife scolded me in her harshest, my-husband-the-child voice. "That's more  than twice the monthly payment you make for that computer!"  she continued as she escalated to screaming. q "I confess! I confess!" I sobbed. "I'm just an on-line junkie. I'm  addicted to my modem! I guess I'll just have to join Modems Anonymous  before I owe my soul to the phone company." S As a counselor for Modems Anonymous, I hear numerous variations of the  preceding story every day. That insidious disease, modem fever, is  exacting a tragically large toll from the cream of our society's computer  users. Modem-mania is sweeping through the very foundations of our  country and there seems to be no stopping it. This disease (yes, it is a  social disease of almost epidemic proportions) is becoming such a calami-  ty that soon there will be a soap opera about on-line addiction, named  "All My Modems."; kON7by Stev" pkNk.k+k*k)kaddict 2 974 If y74 If you don't already own one of those evil instruments called a modem,  take warning! Don't even think about buying one. Modem fever sets in  very quietly; it sneaks up on you and then grabs you by the wallet,  checkbook or, heaven forbid, credit cards.! S Once you own a modem, you enter the insidious addictive trap by "dialing  up" a friend who also has a modem. For some strange reason, typing  messages to each other fascinates you. (Even if it is less than 10% of  the speed that you can speak the same words over a normal voice phone  link.) Of course, you make several attempts at hooking up before you  finally figure out that at least one of you must be in the half-duplex  mode; that discovery actually titillates you (sounds impossible, but it's  true).E S Then your modem-buddy (friend is too good a term) sows another seed on the  road to on-line addiction by giving you the number of a local RBBS  (Remote Bulletin Board Service). Once you get an RBBS phone number,  you've taken the first step in a journey that can only end in on-line  addiction.A e evil ins p(kO'kjjjjaddict 3 9 75M  75M  After you take the next step by dialing up the RBBS, you find that it's  very easy to "log-on." This weird form of conversation with an unattended  computer is strangely exciting, much more so than just typing messages  when you're on-line with your modem-buddy. The initial bulletins scroll by  and inform you about the board, but you're too "up" to comprehend most of  it. Then you read some of the messages in the message section and maybe,  in a tentative manner, you enter one or two of your own. That's fun, but  the excitement starts to wear off; you're calming down. Thinking that it  might be worthwhile to go back and reread the log-on bulletins, you return  to the main RBBS menu.5 M Then it happens. The RBBS provides the bait that entices you all the way  into the fiery hell of modem addiction. As you look at the RBBS main menu  to learn how to return to the log-on bulletins, you find an item called  FILES. By asking your host computer for FILES, you thread the bait onto the hook of corruption; the FILES SUB MENU sets the hook. You start running with the line when you LIST the files; you leap into the air with  the sheer joy of the fight when all those public domain program titles and  descriptions scroll by. They're FREE! All you have to do is tell the g  pjPj`j]j\j[jaddict 4 9 76R bul 76R bulletin board to download (transmit) them to you. You download your first program and you're landed, in the creel, cleaned and ready for  the cooking fires. In just 55 minutes after you logged-onto the board, you've downloaded six  programs. One of them is Andrew Fleugelman's PC-Talk I (truly an in-  strument for evil). 4 O  BBS-LIST.DOC, which is also among the files you downloaded, contains a  list of a great number of bulletin boards throughout the country. (There's  evil all around us, constantly tempting us!) You print the list and find about 60 RBBS phone numbers. (Have mercy on our souls!) The list also  gives you the hours of operation, communications parameters and informs  you about each board's specialty. You decide to try PC-Talk I and use  it to dial-up an RBBS about three states away. Since the line is busy,  you pass the time entering all those RBBS phone numbers into PC-Talk's  voluminous dialing directory..  N Try the number again - still busy. You think, "Hey, there's one that  specializes in Pascal programs. Maybe I'll try it. It's about half-way  across the country, but it's after 5pm and the phone rates have changed. Q to pZjQYjiiiiaddict 5 977R It w77R It won't be too expensive." 2 N The Pascal board answers. After 45 minutes you've downloaded another five  programs. Then you call another board - only this one's completely  across the country, in Florida. And so it goes on into the night . and  the next night . and the next.)  PSome days it gets to you. You begin to feel the dirtiness of modem  addiction, particularly when your wife makes you feel like a child by  berating you for those astronomical phone bills - if she hasn't divorced  you by then. Every time you sit down before your PC to do some work, you  dial up another RBBS instead. If it's busy, you call another, and anoth-  er, until you connect. Then you feel OK, almost "high." When you finally  hang up, you still can't work; you can only dial up another RBBS.  N Your downfall as an on-line addict is just another one of this society's terrible tragedies, such as polygamy or the compulsion to circle all the  numbers on computer magazine "bingo cards." Eventually your whole social  life relies upon only the messages you find on electronic bulletin  boards; your're only happiness is the programs you have downloaded. (You  never try any of them, you only collect them.) The Pasc piRiiiiiaddict 6 9 78M T 78M T Hope exists, however. We, the dedicated but under-paid staff of Modems  Anonymous, have done extensive research to find a cure for modem mania,  which has been ruining hundreds of lives. And we have succeeded in our  quest. The cure is really quite simple, yet effective: set up your own remote bulletin board service. Then all the other modem addicts will phone you, and their wives can nag at them about $450 phone bills, and you can find peace - at last.icated  piSiixiviuiarc1 Q  N 6N BNNN'  NNNNNNNNNNNNQ&ͻ  ͻ 79 ͹ Q U I C K S T A R T ͼ    ͼ  N UNzipping or Reconstructing an ARCHIVE File from a BBS NA BBS is a Computer Bulletin Board Service. People who use this type of service can acquire programs or other information  in the form of ARCHIVE files. These files are picked up via  a modem. In order to use them, they must be RECONSTRUCTED  (UNzipped) through the use of a program such as PKZIP/PKUNZIP  H There are several public domain, shareware and commerical file  compression utility programs available. We have chosen PKware's  PKZIP and PKUNZIP to distribute with our software. D The following page will give the pattern to type to UNzip your files.A L L L L LNͼA BBS is! ptiTsi5iiiiarc2 }6]) N3      ( / 4 5  3@ 5EN;>Q&ͻ&ͻ  ͻ 80 ͹ Q U I C K S T A R T ͼ    ͼ  UNzipping or Reconstructing an ARCHIVE File from a BBS N Follow this pattern to UNzip your files: E  C:>PKUNZIP A:AnyFile.ZIP C:       #  DESTINATION of your choice   -   the NAME and LOCATION of the archive file    Use any MS-DOS file notation   4   The PROGRAM command   The program MUST be located at the prompt position  or.+  The program can be located elsewhere through the   PATH= setting'  I 1   & Nͼ #  piUihhhharc 3 Q.  +  -NKNNNNNNNNNNNNNMMLL CQ3 ͻ 3 ͻ  + 81 Use of PKware in Telecommunications - BBSͼ + N PKware and Phil Katz helped make this program possible!N Compressed or ARCHIVED files pack a lot of information into a small space. PKware file compression methods are the standard used by many successful BBS systems across the country. N Archive files created through PKware assure you of the highest level  of file accuracy. PKware compressed files are the most compact,  meaning they take less telecommunications time to deliver, PLUS PKware is FAST! According to benchmarks published in major computer magazines, you will be able to manipulate your compressed files many times faster with PKware as compared to similar programs on the market. PKware provides YOU with the highest standards of the industry. NK LK K CNͼ phVhwhihhhgharc 4 Q& !$N3 0NN NNNNNNNNNNNNNNQ,ͻ,ͻ "ͻ  82 ͹ Introduction to File Compressionͼ "ͼN 3The term "compression" means to reduce in size. Computer file  compression means that by using PKware programs, files are quickly reduced in size and thereby take up less storage space. This  process, sometimes called ZIPping, creates ARCHIVE files.  IArchive files have three distinct benefits: I 1. They use less disk space than normal files. Archive filing increases the life and storage availability of your expensive hard disk.7 I 2. Many individual files can be stuffed into a single archive file. This makes file group identification, copying, and transporting faster and easier." I 3. Archived files travel faster via modem which reduces  telecommunication transmission and reception.NNͼess pfhWehhGLOSS START &/o 83 ͹ G L O S S A R Y ͼ/ oABORT A procedure to terminate execution of a program.iA/B SWITCH BOX An external device used to switch between one or more devices, such as a modem, a plotter, a printer, or a mouse.d ACOUSTIC COUPLER (also Acoustic modem) A type of modem which connects to aphone line through a coupler which fits onto a telephone handset. It converts electronic data to and from audio signals. (See DIRECT-CONNECT MODEM, MODEM) ADAPTER Also called add-on card, controller, or I/O card. Adapters are installed in expansion slots to enhance the processing power of the computer or to communicate with other devices. Examples of adapters include printer, asynchronous communication, floppy disk controller, and expanded memory.W ADDRESS A numeric value identifying a specific memory location. Addresses are assigned to memory locations permitting reading or writing of data. O ADDRESS SPACE Set of addresses describing accessible memory locations thatcan be occupied by programs or data. Usually the complete range of memoryUure to te  pXL  -catiL84locations that can be accessed by a microprocessor. The microprocessor inyour Personal System can directly address one megabyte of space. This spaceis occupied by both RAM and ROM and can include memory that resides on diskcontrollers, display adapters and other peripheral devices.eALT KEY A key on the keyboard that provides additional functions when usedwith other keys. Basically, this key is an additional shift key._ANALOG SIGNAL A signal that varies in a continuous manner, such as music orthe voice tones carried over telephone lines. A radio or electric signal orsystem that uses variations in amplitude (strength) or frequency on a carrier wave to carry information. (See CARRIER, DIGITAL SIGNAL)_APPLICATION The system or problem to which a computer is applied. The mostcommon applications for personal computers are word processing, businessanalysis using spreadsheets and data processing using some form of databaseprogram.APPLICATION PROGRAMS A program designed to perform a particular task orfunction but does not directly control the computer hardware system functions.APPLICATION SOFTWARE Same as Application Program.m pY;7654Ln3'SCIIL85 ASCII American Standard Code for Information Interchange. A standard seven-bit information coding system that assigns a number from 0 to 127 to each of 128 upper and lower case letters of the alphabet, numbers, special characters, and control characters. An eighth bit is almost invariably added but its use is less standardized. In telecommunication applications the eighth bit is often a calculated parity number, most commonly even. Internally, PC's utilize the IBM character set, which employs eight bits to display 256 characters, symbols, space and null. This character set is used widely with small computers and terminals and can be transmitted from, one location to another using eight bits and no parity. O ASCII DOWNLOAD In general, a download of pure ASCII text. Such a downloadinvolves no error-checking, but is typically governed by XON/XOFF flow control. (See DOWNLOAD, PROTOCOL, XON/XOFF)# O ASYNCHRONOUS COMMUNICATION A type of serial communication by which data ispassed between devices. "Asynchronous" means that the timing of each character transmitted is independent of others. O AT COMMAND SET Also known as the "Hayes command set." This is the industrystandard set of commands which the computer uses to control the modem. The commands begin with the prefix "AT" - for instance, "ATDT" tells the modem to dial (D) using DTMF "Touch-Tone" dialing (T).ohange. A pZ3ކن؆׆ֆL  a  86AUTO AL86AUTO ANSWER A mode in which the modem answers incoming calls automatically, without your intervention.5 PAUTO DIAL Signifies that a modem is capable of dialing telephone numbers in response to computer commands.1 PAUTO LINE FEED A communications parameter which causes a terminal program to automatically perform a line feed (LF) when a Carriage Return (CR) is seen. (See CARRIAGE RETURN AND LINE FEED)% PAUTO LOGON Many communications programs are able to perform your logon sequence for you automatically when connecting to a host system. This is done bymeans of pre-written script files. (See SCRIPT, LOGON) PBACKSPACE The ASCII character Control-H, ASCII 8. This causes most terminals to "back up" (move one space to the left) and delete the character at the new position. (See ASCII, DEL/RUBOUT)" PBACKUP Refers to equipment or systems whose purpose is to provide continued operation when the primary equipment or system fails. A backup diskette is a diskette used to store copies of other diskettes or of data on a fixed disk to help prevent loss of data in case of damage and/or system failure. lly, p[ՆL 7 8BAT AL87BAT Abbreviation for Batch. Used as the file extension (.BAT) for executable files containing DOS commands.wBATCH FILE A file containing commands in a particular sequence, allowingthem to be processed one at a time, automatically. This type of file endswith the extension .BAT.BAUD RATE The actual rate of symbols transmitted per second which may represent more than one bit. Thus a given baud rate may have more than oneBPS rate.BBS (See BULLETIN BOARD SYSTEM)BELL ASCII character 7, Control-G. This causes the receiving terminal toring a "bell" or some sort of alarm sound.vBELL COMPATIBLE Means that a modem is compatible with the BELL 212A modemspecification, which is the standard for 1200 bps modems.gBINARY A numbering system with two digits, "0" and "1" used by computers tostore and process information.BIOS Basic Input-Output System - a collection of primitive computer[ execut p\73210L2< outiL88 routines (stored in ROM on a PC) that control the video display, disk drives, and keyboard.: O BIT A binary digit and the most basic unit of data that can be recognized and processed by a computer. A bit is either 0 or 1. Bits can be groupedto form larger units of information nibbles (4 bits), bytes (8 bits), or words (16 bits - may vary).4 O BITS PER SECOND (BPS) The number of data bits sent per second between twomodems. This is often improperly referred to as the BAUD RATE. (See BAUD RATE) BLOCK During file transfers or other error-checked communication, a block is a group of characters sent together, along with some sort oferror-checking information. Common block sizes are 128 bytes and 1024 bytes.I PBOARD Within an on-line service or Bulletin Board System, a specific message posting/receiving area. Sometimes used to refer to an entire BBS. (See ON-LINE SERVICE, BULLETIN BOARD SYSTEM)s BOOTSTRAP (BOOT) The term "bootstrap" comes from the phrase "pulling oneself up by one's own bootstraps" and means the process by which a smallU video displ p]/܅ۅڅمL 2rogrL89 program in ROM loads other programs into the computer's memory. O BOOTABLE DISK A disk containing the DOS programs necessary to make it "bootable." This consists of the files for Input/Output and DOS, which are"hidden," and thus transparent to the user. The master DOS diskettes have one disk that is bootable, and the others are not. See your DOS User and DOS Technical Reference Manuals for more specific information. PBPS (See BITS PER SECOND)5 O BREAK CHARACTER A character which you send to signal a host system to stop what it is currently doing. The familiar "Break Key" Control-C is a common break character, as are Control-K and Control-P.o BREAK A command that stops an operation. The keyboard has a Break key, however it will only work when used with the Control key. This function of the keyboard is programmable and is not always functional or active, depending upon the product.4 O BUFFER An area of memory where the computer or modem stores incoming or outgoing data until it can be processed or sent.o uter's memor p^؅~}L>,:1 BUG L90 BUG An error. A hardware bug is an electrical, mechanical, or electronic defect that interferes with the normal operation of a computer. A softwarebug is a mistake coded into a program.) PBULLETIN BOARD SYSTEM (BBS) A computer (generally a microcomputer) set up to receive calls and act as a host system. BBS's allow users to communicate through message bases, and also to exchange files. PBUS A group of wires used to carry a set of related signals or information within a computer from one device to another." O BYTE A sequence of adjacent binary digits operated on as a unit by the computer. A byte consists of eight bits.v CAPTURE Communications programs often store, or "capture," the data being sent by the remote system. This data may be saved in a disk file, or in a"capture buffer" which you can scroll through and examine. O CARET The symbol ^, found above the number 6 on most keyboards. PCARRIAGE RETURN (CR) ASCII character 13, Control-M. Generated by the RETURN or ENTER key, this causes the cursor to move to the first column on the screen. (See AUTO LINE FEED)~ic p_|.)('&Lt: 8 CARRIL91 CARRIAGE RETURN AND LINE FEED On IBM-Compatible systems and others, this combination is the standard End-Of-Line marker. When displayed by a systemit causes the cursor to move down one line, and also to return to the first column. (See CARRIAGE RETURN, LINE FEED, AUTO LINE FEED) PCARRIER The basic signal sent over the phone lines which modems use to transfer data. This is the tone which is modulated to signify bits of data. (See MODULATE)A PCATHODE RAY TUBE (See CRT)4 PCENTRAL PROCESSING UNIT (See CPU)- O CCITT COMPATIBLE Means a modem is compatible with the CCITT (the International Consultive Committee for Telephone and Telegraph) V.22bis standard for 2400 BPS communications. Hayes-compatible 2400 baud modems are CCITT compatible.> O CHARACTER A symbol found on the key of a computer keyboard. The symbols include the numerals 0 to 9, the letters A through Z, punctuation marks,control symbols, and other special signs.& O CHECKSUM A method of error-checking which involves adding up all charactersSs p`%ԄЄτ΄̈́L  ,L92 sent, and comparing the lower byte of the result to an identical checksumsent along with the data.6 PCHIP (See INTEGRATED CIRCUIT)1 O CLONE A term used to describe an IBM-compatible computer. O COLD START To turn on the power switch of a computer to begin itsoperation. If the computer is already on, to turn off the power switch and then to turn it on again. After a cold start all the devices of the computer are reinitialized. (Also called cold boot or cold reset) PCOM 1) Designation for a serial communication port when followed by a number, as COM1, COM2, etc. 2) Short for COMMAND when used as a file extension as in "DISKCOPY.COM". Files with the .COM extension are executable by entering the name by itself without the extension. (See EXE)S COMMAND The portion of an instruction word which specifies the operation tobe performed. A program that can help you to create, change, analyze, or move data and software. DOS has two types of commands, Internal and External.F O COMMAND.COM COMMAND.COM is sometimes referred to as the "command^ an identi pārnmlkL  ~.interpL93interpreter," the "console command processor," or the "shell." Used by DOS to interpret your commands and execute programs. O COMMAND LINE The line on which the system prompt appears and commands are entered in to the computer. The command processor supplied with DOS. Itacts as the interface between your input and the other components of the operating system, by interpreting all commands and performing executable functions.E O COMMAND MODE A communications program in command mode is ready to acceptuser commands. (See TERMINAL MODE), O COMMUNICATION BOARD Communication is the process of transferring information over various media from one point or device to another. Thereare several products that can be installed inside a computer, as an internal product. The more common uses are modems and local area networks. N COMMUNICATIONS LINK The path of data transfer through the various components involved in communications between two computer systems; for example, the modem, telephone line, packet-switched networks, etc. N COMMUNICATIONS PARAMETERS These are settings which determine how your communications software will interpret incoming data, and what type of dataT pbj LE* %9 bL94will be sent out. The most important parameters are bits per second, parity, data bits and stop bits. (See COMMUNICATIONS SOFTWARE, BITS PERSECOND, PARITY, DATA BITS, STOP BIT)|COMMUNICATIONS SOFTWARE The software you use to control your modem. Thisis the software which handles terminal emulation, file transfer, dialing andall modem input and output.COMPATIBILITY Capable of orderly, efficient integration and operation withother elements in a system. IBM products have become a "Standard" in theindustry, and for this reason PC manufacturers attempt to produce products "compatible" with the IBM products. NO COMPUTER ON THE MARKET CAN BE 100% COMPATIBLE BECAUSE OF RIGHTS OWNED BY IBM REGARDING THEIR BIOS FIRMWARE ANDBASIC LOCATED IN ROM.: O COMPUTER Any device that can receive and store a set of logic and arithmetic instructions and information, process the information in a predetermined way, and communicate or store the results. O COMPUTER PORT See Port, COM1, or LPT1.( O COMPUTER SYSTEM A group of hardware consisting of a computer, a video display, a keyboard, memory, and storage media, in its minimumare bits per  pc L> ( : 495 confiL95 configuration. Any number of additional devices may be added to make a system faster and more functional.- PCON Short for console which historically included both the keyboard and the monitor. In a personal computer, console is often used to designate thekeyboard by itself.< O CONFERENCE Also called SIG (Special Interest Group). A conference is an area set up as a "Mini BBS" inside the main BBS. Conferences include separate message bases, file transfer areas, bulletins and doors.Conferences are topic specific and may cover such subjects as Politics, Desktop Publishing, Games and Product Support.! O CONFIG.SYS An ASCII file containing sub commands for the completion of theboot sequence and configuration of certain system characteristics. O CONNECT This is the point when two computers connect by modem. Modems usually display a message "CONNECT" when the two modems recognize one another.G PCONNECT TIME The amount of time spent connected to another system. This is generally expressed in hours, minutes and seconds; sometimes it is expressed in fractions of hours, especially in online services with a per-hour connectSmake a  pdhcba`L >>96 chargL96 charge.H PCONTROL CHARACTER Keyboard character used for a control function. Form feed and line feed are examples of control characters. O CONTROL KEY A key on the left side of the keyboard that is used in combination with other keys to perform certain functions.f CPS The number of characters being sent per second during a communications session. CPU (Central Processing Unit) The central processor of the computer system that controls the processing routines, performs the arithmetic functions,and has a quickly accessible memory.+ O CRC (Cyclic Redundancy Checking) A method of error checking used in laterversions of XMODEM file transfer to cut down on errors when transmitting data.J O CROSSOVER CABLE (See NULL MODEM)~ CRT (Cathode Ray Tube) An electronic vacuum tube containing a screen on which information may be displayed. Most computer monitors, all standard TVStrol func pe_L  ; L97 sets and oscilloscopes use CRT's.~ CTRL-ALT-DEL A three-key command that resets the PC and initiates a reboot of the system.A PCTRL-BREAK A two-key command that generally interrupts a program. This key combination usually has the same effect as CTRL-C. PCTRL-C A two-key command that generally interrupts a program. This key combination usually has the same effect as CTRL-BREAK. PCTRL-S A two-key command that generally stops a program, which freezes the screen for viewing. In some programs this is a "toggle," or switch, i.e. press the combination a second time and the program continues.a CTS (Clear to Send) An "OK to send data" signal generated by the modem or the serial card.? PCURSOR A special symbol on a screen showing the position where a character can be typed or corrected.5 PDATA Information of any type, including binary, decimal, or hexadecimal numbers, integers, strings of characters, etc.q A three-ke pfȂ‚L    698 DATA L98 DATA BITS The bits sent by a modem which actually make up a character of data; this does not include stop, start or parity bits, which are used onlyby the modem and not passed on to the computer. As a communications parameter, this specifies the number of data bits the modem will use. (See BIT, START BIT, STOP BIT, PARITY). O DATA WORD (See CHARACTER)5 PDCE (Data Communications Equipment) A modem or other device used to transfer data between two computers.{ DEFAULT The value entered by a program when you don't enter a value. PDEFAULT DRIVE A drive to which the system looks to read or write information unless another drive name is specified in a given command. Initially, the default drive is the one from which DOS is loaded into memory when the system is first booted up., O DELETE To remove a file from disk storage.$ PDEL/RUBOUT ASCII 127. On some systems, this performs the same function as backspace. (See BACKSPACE) of pghcba`L 8 ; 4 3DELIMIL99DELIMITER A character used to separate other characters in a file or command. They may be, for example, SPACE (One character space, blank) TAB (A group of spaces) COMMA (,) SEMICOLON (;) EQUAL SIGN (=) PLUS SIGN (+). PDEMODULATE To convert the modulated carrier tone sent by a modem back into data. (See MODEM, MODULATE)3 PDENSITY The amount of space distribution on a storage medium, such as magnetic storage on a disk or visual storage on a video monitor (CRT) PDEVICE A piece of equipment that is used to input data for processing or to output processed data. DOS provides access to several devices by use of reserved names such as: A:, COM1:, PRN, AUX, CON, and etc. PDEVICE DRIVER A program created to control a particular device. DOS loads a Device Driver into memory at boot-up time. External device drivers are usually listed in the CONFIG.SYS file.) PDIAL-UP Call one modem from another, over telephone lines. PDIAL-UP MODEM A modem designed to be used over telephone lines. Due to the problems of phone line noise and signal loss, to be effective a dial-up modem must operate within a certain lower bits-per-secondfr com ph_ K 73> } 100rangeK100range (typically 9600 bps or less). (See DIRECT-CONNECT MODEM, BITS PERSECOND)DIAGNOSTIC As a noun, short for Diagnostic Program. A computer programdesigned to 1) determine if a malfunction exists and if so, 2) locate themalfunction in the computer and/or the attached peripherals.dDIGITAL SIGNAL An electrical signal which takes on only certain values (e.g. 1 or 0) and is not continuous. A digital signal is either on or off -there is no modulation as with an analog signal. (See ANALOG SIGNAL)[DIP Dual In-line Package. It is the most popular packaging method for integrated circuits. It has two parallel rows of pins. The numbers of pinsusually come in 14, 16, 18, 20, 24, 40, or more.pDIP SWITCH A multiple miniature switch in the form of a DIP.cDIRECT-CONNECT MODEM A modem which is intended to be connected by a dedicated cable to another modem. Since they do not have to operate overphone lines, direct-connect modems can move data much faster than dial-upmodems. (See DIAL-UP MODEM)DIRECTORY A list of file names and locations of files on a disk. A[ER piK. 7 ireK101 directory may point to directories called sub-directories, but the DOS master directory is the ROOT Directory.( O DIRECTORY STRUCTURE Refers to how a directory is organized and arranged on a disk. A structure can grow large and complex, but the basic organizingblocks are the dot and dot-dot files found in each sub-directory. O DISCONNECT (also LOGOFF, LOGOUT, SIGNOFF) The termination of the connection between two modems. In communications software, the command that causesthis termination.> O DISK A circular metal platter or mylar diskette with magnetic material on both sides, which stores programs and data. Disks are rotated continuouslyso that read/write heads mounted on movable or fixed arms can read or write programs and data from and to the disk.x DISK DRIVE The motor that actually rotates the disk plus the recording - playback heads and associated mechanisms all in a mountable housing. O DISKETTE A diskette serves the same purpose as a disk (above) except it ismade of flexible material and is permanently enclosed in a protective jacket. Also called floppy disk..  pjMHGFEK  9102 DISKK102 DISK FORMAT Refers to the method data is organized and stored on floppy or hard disk. There are many "standards" in the personal computer marketplace, however the most widely used and accepted is that used by DOS for the PCfamily, which is 48tpi, DS/DD (Double Sided Double Density). O DOORS An area found on most BBS systems where a user can exit the main BBS program and run any of several stand alone programs. Doors include Gamessuch as Trivia, Poker and Checkers, plus utility programs that will amortize a loan, or allow use of the latest high performance file transfer protocols. O DOS (Disk Operating System) A set of programs that controls the communications between the components of the computer. Examples are displaying, reading and writing to a disk, printing, and accepting commands from the keyboard.= PDOT FILES Files found in a sub-directory that contain information as to current and parent directories.0 O DOWNLOAD To receive data, typically a file or files, from the host system.This is often done using some sort of protocol, such as XON/XOFF or an error checking protocol such as XMODEM. (See PROTOCOL, XON/XOFF) O DRIVE D A reference designator for a drive, which could be drive A or B forSloppy o pkDK u flopK103 floppies, and C for a hard disk. This is commonly used because the software author does not know what environment the reader or user is in. O DTMF The "Touch-Tone" dialing system used by many phone systems.^ DTR (Data Terminal Ready) A signal in your modem or serial card indicating the modem is ready.< O DUPLEX Data communications that can handle simultaneous two-waycommunications. Also a communications parameter used to determine whether or not your computer's keystrokes will echo on your screen or the screen of the computer you are connected to.} ECHO If "Echo" is yes, the character you typed on the keyboard is displayed on the screen and sent to the host., PECHO NETWORK Bulletin Board Services often join in a message base exchange where one centrally located board will act as a "Host" and other boards will call to upload messages entered by its users and download messages left by other boards in the network. The effect is that a local BBS user may ask aquestion about Database programming, and be answered by a user in another state or country. pl뀗K<# 104 EDITK104 EDITOR A computer program that allows users to create and modify text files, similar to a word processor, but usually much simpler. Often used to create/modify computer programs, hence their output is in a basic text format without the various control characters that word processors use. EDLIN is the name of the editor provided with either PC or MS DOS.] EDLIN A DOS utility that enables you to create, edit, and display source program and text files. EDLIN is a line editor.o ENTER (See CARRIAGE RETURN)4 O ENTRY One item of information in a database, or one item in a list. Also, all the information pertaining to one on-live service in a communications program's dialing directory.3 O ELECTRONIC MAIL (E-Mail) The exchange of messages via a bulletin board service or on-line service. One user leaves the message on the service "addressed" to another user. When the other user later connects to the same service, he can read the message, reply to it, etc. Through many online services E-Mail can be sent and received by users separated by thousands of miles.EMULATION (See TERMINAL EMULATION)|  pm610/.K 6 %>2ERRORK105ERROR-CHECKING PROTOCOL (See PROTOCOL)yESCAPE CODE The hex equivalent of ESCAPE is 1B. Normally, what follows iscalled an escape code. The codes that follow usually have specialsignificance, especially in terminal emulation files.kERROR MESSAGE DOS displays error messages when it encounters problems whileattempting some system functions. Some common error messages are SEEK, NOTREADY, WRITE FAULT WRITE PROTECT. System errors respond with a message andprovide an option to the user of Abort, Ignore, and Retry. DOS commandshave error messages for each of the commands as it relates to the specialneeds of that command. Refer to your DOS manuals for specific details.YESC Abbreviation for ESCAPE. The legend on the ESCAPE Key on personal computer keyboards. Also, the character generated by pressing this key. PEXE Abbreviation for Executable. Used as a file extension in DOS (.EXE) in certain types of executable files. Similar in use to files with the .COM extension. (See COM): PEXPANSION SLOT Long, narrow edge connector on the system board, into which adapters and other add-on cards to expand the functions of the computer are inserted.valent o pn-K<=106 EXTEK106 EXTERNAL MODEM A modem which is used as a separate unit from the computer, connected through the computer's serial port. (See INTERNAL MODEM)\ FIELD Within a database or other collection of data, a field is one specific part of a record. For instance, in a database of user information,"name" might be one field, "password" might be another, and so on. O FILE A collection of related records treated as a unit. In a computer system a file can exist on magnetic tape, disk, or as an accumulation ofinformation in system memory. A file can contain data, programs, or both. O FILENAME Alphanumeric characters assigned to identify a related set of records which constitute a particular file. DOS allows a filename to haveup 8 characters and an extension name of up to 3 characters. Certain characters cannot be used in the name or the extension. See your DOS User Manual the DOS Technical Manual for more specific information.a FILE TRANSFER PROTOCOL (See PROTOCOL)) O FIRMWARE Software stored in a permanently preprogrammed ROM (Read Only Memory) chip which performs tasks such as hardware diagnostics, initializing the system, and bootup.8  pob^]\[K x w   FIXEK107 FIXED DISK Also known as HARD DISK or WINCHESTER. An early IBM disk drive was named the 30-30 (like the rifle), thus the nickname "Winchester" sprang up. A bulk storage system with non-removable rotating rigid magnetic storage disks. Typical storage capacities range from 20 Megabytes on up to over 10 Megabytes for personal computers and much higher in large sizesfor large computer systems. (There are some versions of hard disk with removable rigid media in the form of disk packs)o FLOPPY DISK Also known as FLEXIBLE DISK or DISKETTE. A bulk storage system with removable rotating flexible magnetic storage disks. These come in 8-inch, 5 1/4-inch, 3 1/2-inch and 2-inch. The 5 1/4-inch and 3 1/2-inchare the most common for personal computers. The 3 1/2-inch and 2-inch disks are found on some laptops. Typical storage capacities range from 360 Kilobytes to 1.2 Megabytes on 5 1/4-inch diskettes and from 720 Kilobytes to 1.44 Megabytes on the 3 1/2 and 2-inch diskettes. O FLOPPY DRIVE A disk drive designed to read and write data to a diskette for transfer to and from a computer. It is available in 3 sizes, 8 inch, the standard 5 1/4-inch, 3 1/2-inch, and the newer 2-inch. The 5 1/4-inch modelcomes in two sizes, full height and half height, with the half height requiring less power and less space. (See DISKETTE) O FLOW CONTROL A method used between two devices to regulate the flow ofX An early ppZ~~~~K6;  6 ataK108 data. Typically, there is a signal to stop sending data, as well as a signal to start sending again. Between directly-connected devices (such asa computer and a printer) this is usually done by the hardware. Between two modems, software flow control is used; one character (such as XOFF) signals the modem which receives it to stop sending data until another character (such as XON) is received. (See XON/XOFF)% O FORMAT Noun A predetermined method of arranging characters, lines, punctuation, etc. Verb to prerecord the physical organization of tracks and sectors on a disk.= O FRAMING BITS Used to describe the bits which "Frame" a character sent by modem - the Start and Stop bits. (See START BIT, STOP BIT) O FULL DUPLEX In a full duplex communications system, characters sent to the host are echoed back by the host to your screen. If your host computer usesfull duplex communication, you should usually set "Echo" to "No". O FUNCTION Used in DOS to indicate the name of a command that is to be invoked the command line. FUNCTION KEY A special key used by itself or in conjunction with other keys to perform user defined operations, or functions. There are 10 such keys,Us pq~~~~~~KE@q 6; 5109 labeK109 labeled F1 through F10. DOS uses these keys for editing the command Line and working in EDLIN and FUNCTION KEY. The keys labeled F1..F12 often usedas program command keys.7 O G The international symbol for giga, meaning billion. In computer usage itis defined as 1024 times mega and is actually 1,073,741,824, which is also 1K times 1M. (See K, M)7 O GATEWAY An ad-hoc connection between two on-line services. A gateway exists when you are provided with a means of accessing one on-line service through another. For instance, users of CompuServe can access MCI Mail.W HALF DUPLEX In half duplex communications systems, characters sent to the host are not echoed back to your screen. If your host uses half duplex, set your "echo" to "No". HANDLE A pseudonym used on a BBS or online service in place of your real name, similar to CB radio handles. Handles are particularly popular with players of online games. HANDSHAKING The devices at either end getting "in sync" with each other's behavior. This may be a hardware handshake, or a setting of certain software behaviors.mand Line pr~S~N~M~L~K~K:  NGK110 HANG UP The modem "hangs up" the phone line; this has the same effect as hanging up a phone when you are through talking - the other end isdisconnected, and the "conversation" is terminated. O HARD COPY A printed copy of machine output in a visually readable form. PHARD DISK (See FIXED DISK)4 O HARDWARE The physical components of a computer. PHAYES COMMAND SET (See AT COMMAND SET)( PHAYES COMPATIBLE Hayes compatibility means two things. First, that a modem uses the same communication standards as the industry-standard Hayes modems.Second, that the modem also obeys the AT (or Hayes) command set. (See AT COMMAND SET, BELL COMPATIBLE, CCITT COMPATIBLE)p HERTZ (HZ) A unit of frequency equal to 1 cycle per second.c HEX Short for HEXADECIMAL, a 16 digit numbering system used in computers. Each HEX digit represents 4 binary digits, hence 2 HEX digits can be used to represent 8 binary digits or 1 Byte. The 16 digits used are 0-9 and A-F.  psJ~}}}}}K 6K1HOST SYSTEM This is, in general, the system to which you are connected whenyou call a BBS or on-line service. The host system receives calls, presentsmenus, accepts commands from the local system (your system), etc._IBM-AT The AT is the "Advanced Technology" personal computer, the thirdgeneration upgrade from the IBM-PC. This product uses the 80286 processorand many advanced features not available with earlier computer models, suchas 1 million bytes of RAM (or more), and faster computer speeds.`IBM-PC The original personal computer from IBM, this product came standardwith 2 floppy diskettes and 64K RAM. All kinds of upgrades were availablefrom other companies because of the its "open architecture," which meantthat IBM allowed everything about the computer to be know to the world.X ROM The Read Only Memory is the component that contains the programs and data needed to start and operate the computer and its peripheral devices. This device is copyrighted by IBM and holds the major key as to compatibility by software and hardware devices.p IBM-XT The 2nd generation of IBM microcomputers. Based on the same processor as the original PC, the XT introduced hard disks. (See FIXED DISK)J are pt}}}}}}K, ~ IC K112 IC See (INTEGRATED CIRCUIT)3 PID (also USERID, USERNAME) The "name" which is assigned to you by a given BBS or on-line system. This is entered by you when you log on to the system,and identifies you to the system. It may be your real name, a handle, or some string generated by the host system. (See HANDLE) O INITIALIZATION STRING A command or group of commands sent to the modem by a communications program at start-up. This will tell the modem to use a certain setup which the program needs to correctly communicate with it. O I/O Input/Output.= PINPUT (Noun) Data that flows from external devices to a computer. (Verb) To send data from external components.y INPUT/OUTPUT Data transferred from external devices to the computer or from the computer to external devices.~ INTEGRATED CIRCUIT A tiny complex of electronic components and their connections that is produced in or on a small slice of material (such assilicon). A single IC can hold many electronic elements. These IC's are typically packaged in DIP's. Also called CHIP.pname"  pu};}7}6}5}4}K 2ERK113INTERFACE An exchange of information between one device and another or thedevice that makes such exchange possible.& O INTERNAL MODEM A modem which resides inside the computer in the form of anadd-in board. (See EXTERNAL MODEM), O K The international symbol for KILO meaning thousand. In computer usage itmeans 2 to the power of 10, or 1,024. When applied to individual memory (RAM or ROM) chips, the term usually means 1,024 bits. It is often applied to banks or whole populations of memory, then meaning kilobytes or KB. (See G, M)J O KERMIT A file-transfer protocol designed for maximum portability. Kermithas features which allow it to be used between any two computers which support modems, regardless of system differences. However, because of its emphasis on flexibility, Kermit is very slow and should not be used when faster options are available.2 O KEYBOARD BUFFER An area of memory that stores information from the keyboard. This memory area can be programmed by the user and software to enhance editing and control functions.) O KHZ (Kilohertz) 1,0 Hz. device and  pv3}|||||K>!> 6 KILOBK114KILOBYTE (K bytes or KB) 1024 bytes.* PLAN (Local Area Network) A small/moderate sized network in which communications are usually confined to a confined area, such as a single building or campus.< PLEASED LINE MODEM Something of cross between a direct connect modem and a dial-up modem. The modem still works over a telephone or similar line, and across long distances. However, the line is dedicated to this purpose, and is specially conditioned for data transfer. This allows faster communications (greater than 9600 bps) with fewer errors. (See DIRECT-CONNECT MODEM, DIAL-UP MODEM)+ PLED (Light Emitting Diode) An element that is illuminated when an electronic signal is applied (voltage), used as an indicator for the presence of activity.: PLINE EDITOR An editor program that allows editing on a line by line basis. Such an editor may or may not have editing control upon data within a line, however DOS provides that function with the function key editing features. PLINE FEED ASCII 10, Control-J. This causes the cursor to move down one line. On some systems this is the complete "new line" sequence, and alsoV sma pw||||||K / K115causes the cursor to return to the first column. (See CARRIAGE RETURN ANDLINE FEED, AUTO LINE FEED)LINE NOISE When you are using a modem over the phone lines, interferenceand other disturbances cause some noise to creep into the transmission. Thiscan garble characters, cause invalid data to be received, and at worse causea loss of carrier and disconnect.LOCAL AREA NETWORK A communication system designed to connect several computers together so that they may share data and resources (such as a printer or hard disk).LOCAL SYSTEM The system initiating a call to a host system (such as a BBSor online service). Usually, the local system is your system.bLOGOFF (See DISCONNECT)LOGON The act of establishing communications with a host system. This includes both establishing a modem connection, and entering your ID, password, and whatever else the system needs to know about you atconnection. (See AUTO LOGON)LPT1 The first parallel port on the IBM-PC. (See PARALLEL PORT)^ee CARRIA px|'|"|!| ||K :116 M TK116 M The international symbol for MEGA or MEG meaning million. In computerusage it is defined as 1,024 kilobytes, or 1,048,576 bytes. (See K, G) O MACHINE LANGUAGE Instructions and data coded in binary numbers. This is the only language recognized by the microprocessor that controls all operations in your Personal System. All programs and all information to beprocessed by the system get translated into machine language. O MACRO A series of keystrokes, commands, or other actions to be performed by a program, "assigned" to one key or command. As a simple example, many communications programs let you assign your password to a function key so that it can be sent to a host system with one keystroke. PMAIN MENU The "top-level" menu of a program or system. This would be seen either upon running the program, or when you first invoke the programs menufunction. A main menu might lead to various sub menus, reached by selecting options from the main menu.4 O MEGABYTE One million bytes, abbreviated MB, such as 10MB. PMEMORY A device that stores data in a computer. Internal memories are very high speed and are either read/write Random Access Memory (RAM) or Read Onlymputer py|{{{{{K;3:  orK117Memory (ROM). Bulk storage memories are either Fixed Disk, Floppy Disk, Tape or optical memories which hold very large amounts of data but are much slower than the internal memories.- O MEMORY ADDRESS A value assigned to a memory location. An addresscorresponds to the location of a single byte. The address of a memory location may be expressed in hexadecimal or decimal. O MEMORY LOCATION A unique address that can be filled with a specific value. PMESSAGE A computer "note" left by one user of a system for another (or all) to read. The system stores the message until the recipient logs on, at which point he may read it, reply to it, etc." O Mhz (Megahertz) 1,0 KHz, or 1,0,0 Hz.s MICROCHIP Any integrated circuit on a chip. May be a group of electroniccomponents or even a microprocessor (miniature computer) O MICROCOMPUTER (See MICROPROCESSOR), O MICROCOMPUTER CHIP Large scale integrated circuit designed to perform the major functions of a computer (microcomputer, personal computer). TheYDisk, pz{o{k{j{i{h{K =K118 products used in the IBM-PC family of computers are designed and manufactured by INTEL. The IBM-PC uses the 8088. The IBM-XT also uses the8088, and more recently been upgraded to use the 80286. The IBM-AT uses the 80286. Newer models are using the 80386, 80486 and i860.f MICROPROCESSOR An IC or integrated circuit that communicates, controls and executes machine language instructions.( PMILLISECONDS One-thousandth of a second, abbreviated as ms, such as 10ms. PMODE A condition or set of conditions, parameters, or protocols under which an operation can take place. Some examples are color or monochrome display modes and serial communication protocols.v MODEM Acronym for MOdulator/DEModulator. A device that allows a computerto communicate with other computers over various transmission lines. Most MODEMs in use with personal computers communicate over telephone lines at speeds of 300, 1200 or 2400 BPS in a serial mode. O MODULATE Changing the frequency, wavelength or some other characteristic of an analog signal in a way that may be interpreted as data by the receiver. PMONITOR A black-and-white or color CRT display consisting of rows andY p{g{{{{{{K, 6lumK119columns of elements.; PMOUSE A device used to control the cursor and provide some user defined editing functions for software programs.' O MS-DOS Microsoft Disk Operating System - the operating system adapted byIBM for the personal computer family runs on Intel microprocessor series 8088 and later. Version 1 came with the PC, version 2 with the XT, and version 3 with the AT. The operating system controls the components of a computer system, and the system's use and execution of software programs, called "application programs." MULTIPLEXER A device that takes low-speed inputs from a number of terminals and combines them into one high-speed data stream for simultaneoustransmission on a single channel.. O NIBBLE Four bits, or one-half byte. Usually described by one hexadecimaldigit.I O NRAM Non-volatile RAM. Unlike normal computer memory, NRAM does not loseits contents when the system is turned off. This is used by many modems (particularly internal modems) to store configuration information (in place of the switches used on other modems). (See RAM)nrol th p| {zzzzzK 79:1 NULLK120 NULL MODEM A cable used to connect two computers via their serial ports. The cable is wired such that the two computers can send and receive information just as if there were modems at each end. O OFF LINE The modem state when it is not connected to another modem. Most communications programs display an "OFFLINE" indicator when not connected.(See ON LINE)B O ON LINE The modem state when it is connected to another modem. Most communications programs display an "ONLINE" indicator when not connected. (See OFF LINE)A O ON-LINE SERVICE A service which, for a fee, allows users to connect to its computers and receive or exchange information, messages, and/or files. Manyon-line services offer databases, news, shopping services, games, and many other services. (See BULLETIN BOARD SYSTEM)# O OPERATING SYSTEM A set of programs residing in ROM and/or on disk that controls communications between the components of the computer and the programs run by the computer.2 O OPERATIONS GUIDE (See USER MANUAL) p}zcz^z]z\z[zK+   OPERK121 OPERATIONS MANUAL (See USER MANUAL){ OUTPUT (Noun) Data generated by the computer and transferred to an external device. (Verb) The process of generating such data. O PACKET (See BLOCK) PACKET-SWITCHING NETWORK A data communications service that transmits data from one computer system to another in the form of packets. These networks typically provide a nationwide system of local phone numbers (called nodes)allowing access to on-line services without long-distance charges. Some examples are TYMNET, TELENET, DATAPAC. (SEE ON-LINE SERVICE)b PARALLEL COMMUNICATION Transmission of data between two computers of devices, with groups of bits (typically characters) sent at once over several separate lines.8 PPARALLEL PORT A port that transmits or receives 8 bits (1 byte) of data at a time between the computer and external devices. DOS currently recognizesthree parallel ports and names them LPT1, LPT2, and LPT3. LPT means "line printer" as the port was originally expected to only be used with a printer. O PARAMETER A value selected to specify desired outcomes (from the executionTnerated by t p~ZzzyyyyK= 2of a K122of a command or process).6 O PARITY A very simple means of error-checking. Basically, after a set of bits (a character) is sent, another bit is sent to make sure that the totalnumber of 1 (ON) bits sent is either even or odd. With EVEN parity, for example, if three bits were ON in the character, then the parity bit would also be ON (for an even total of four ON bits). Apart from EVEN and ODD, other parities used are MARK and SPACE parity (the parity bit is always OFF or ON, respectively), and NO parity, which is the most common among microcomputer applications.4 O PASSWORD A word used in addition to your USERID to confirm your identity toa host system. While your USERID is public (so that others can send you messages and so on), you password is private - this prevents someone from logging on with your ID and doing damage or (with an on-line service) costing you money.= O PATH An order to follow when proceeding from one place to another. Used in directories to describe the relationship between files and directories. (See PATHNAME)A PPATH NAME A list of directories that DOS follows in order to find a given file.mple means  pyyyyyyK 9123 PC-DK123 PC-DOS Personal Computer Disk Operating System - the operating system developed for IBM by Microsoft. (See MS-DOS)r PERIPHERAL A device that performs a function and is external to the system board. Peripherals include displays, disk drives, and printers. Some peripherals, such as disk drives and peripheral memory, are internal to thesystem unit.C O PERSONAL SYSTEM A microcomputer system that is suitable for dedicated useby a single user.> O POLLING A computer's act of continuously checking the status of some deviceor activity, waiting for a certain event.& O PORT The channel or interface between the microprocessor and peripheral devices.G PPOST To leave a message on a host system, intended for another user or group of users. Sometimes used to mean the message itself. (See MESSAGE) PPROFILE Information an online system keeps about you, to adjust its behavior when you are logged on. This might include your USERID, password, address, interests, color or terminal selections, access level, accountX  pyRyNyMyLyKyK: tatK124 status (on an on-line system), etc. (See ON-LINE SERVICE, BULLETIN BOARDSYSTEM)H O PROGRAM A sequence of instructions created to perform a specific function.Also known as SOFTWARE on computers to distinguish it from the actual HARDWARE comprising the computer and its peripherals. (See SOFTWARE) O PROM (Programmable Read Only Memory) (See MEMORY, ROM) O PROMPT A symbol or message indicating readiness to accept an input.[ PROTOCOL A set of "rules" regulating some form of computer communication. This might be a flow-control protocol such as XON/XOFF, or an error-checking protocol for file transfers such as ZMODEM. The error-checking protocolsmonitor certain information sent with each block of data (such as a checksum or CRC); if the received data does not match the check information, the system notifies the sender that an error has occurred, and asks that the block be resent. This continues until all data has been received (the signal for which is also part of the protocol), or the transfer is aborted for some reason.? O QUALIFIER (See SWITCH)8 yE SERVICE, B pJyxxxxxK 125 RAM K125 RAM (Random Access Memory) A storage medium in which access time is effectively independent of the location of the data. PRAM BIOS BIOS transferred to RAM for faster system operation. PRAM DISK A disk emulator. A portion of the computer memory is reserved for use as a disk drive. Instead of saving information on a physical disk the information is saved in RAM. RAM disks pass data more rapidly than physicaldisk drives, but when their power is turned off all information is lost. A RAM disk is sometimes called a virtual disk.s READ/WRITE HEAD The magnetic head that reads and writes data to or from a disk.J O RECORD A unit of data.8 PREMOTE SYSTEM (See HOST SYSTEM)/ O ROM (Read Only Memory) A storage medium in which data is stored permanentlyand cannot be altered. The data in ROM remains intact even when the power is turned off. ROM is used to store important programs such as the BIOSwhich interprets the codes sent by the keyboard, self-tests the system, and attempts to read a boot sector on the diskette in drive A each time theXime is ef pxxxxxxKB eK126 power is turned on. (See BIOS)0 O ROOT DIRECTORY Master directory of the DOS Operating System. See Directory.E PRS-232 A standardized serial connection system for computers. O RUBOUT (See DEL/RUBOUT) SCRIPT A set of commands which instruct a communications program to performsome task automatically. For instance, a script might contain the commands needed to log on to a system, read and capture all messages, download a file, and log off.= O SCROLL To move the text up or down on a display screen. O SEARCH To look for specific information in an on-line database._ SERIAL COMMUNICATION Transmission of data between two computers or devices,one bit at a time. (See PARALLEL COMMUNICATION) PSERIAL PORT A port that transmits or receives data one bit at a time. DOS recognizes two serial ports and names them COM1 and COM2.frectory of pxfxax`x_x^xK  2 SHIFK127 SHIFT KEY Two keys are on your keyboard, one on each side, labeled SHIFT. These keys allow the selection of upper case letters and characters, muchlike a typewriter shift key and provide additional key options when used correctly.E O SIG (See CONFERENCE): PSIGN-ON (See LOGON); PSOFTWARE Programming tools such as languages, assemblers, and compilers, control programs such as operating systems, or application programs such aselectronic spread sheets and word processors. Software instructs the personal system to perform tasks. (See PROGRAM) O START BIT The first bit in a set of data. It signifies that what follows is the data. STOP BIT The last bit in a set of data. It signifies that the set of data has been sent. STORAGE DEVICE A place to store data, which may be tape, floppy, hard, or optical disk.xbeled SHIFT. p]xK  UXSTORAK128STORAGE MEDIA The storage of data on the surface of magnetic disks, which may be in the form of a hard, or floppy disk." PSTRING A group of successive characters. "ABC" might be a string, as well as a succession of numbers.4 PSUB-DIRECTORY A directory located in another directory. There is no limit as to how many sub directories can be present, other than the physical size of the disk media. All sub directories have a dot and dot-dot file to indicate the present and parent directories.# PSUB MENU (See MAIN MENU)6 PSUPPORT A system or device that allows a certain feature or activity, or provides the necessary equipment it, is said to "support" that feature. PSWITCH A software term to indicate that an option is available that will provide additional functionality. For example, when using the SORT utility you have the "switch option" of /R, which will instruct SORT to work in reverse, or sort from Z to A.2 PSYNCHRONOUS COMMUNICATION A system of data transmission dependent on the precise timing of the transmitted data, and on the synchronization of theVich pK /;129sendiK129sending and receiving mechanisms.SYSOP Short for SYStem OPerator, this is the person responsible for thesetup and maintenance of a Bulletin Board System or other on-line service.He has complete control over the system: who can log on, how many files canbe downloaded, what types of messages can be left, etc. They also usuallyprovide help and advice regarding use of the system.lSYSTEM A generic term for a computer and its equipment, or for an on-lineservice or Bulletin Board Service.~SYSTEM CALL It is used to indicate to the system to generate an interruptfor the computer hardware's operation. The system will wait for the computer to acknowledge the interrupt and perform the task and return control to the computer.TELECOMMUNICATIONS In general, the communication of information by electronic means. In particular, the use of computers to exchange data bymodems, especially over telephone lines.xTELEX An international system of communications by which you can send amessage from any TELEX terminal in the world to any other TELEX terminal, ora computer emulating a TELEX terminal. (See TERMINAL EMULATION)_r, this  pKFEDCK* 130TERMIK130TERMINAL An input/output device designed to receive data in an environment associated with the job to be performed. It is capable of transmitting entries to end obtaining output from the system of which it is a part. A "Smart Terminal" uses a microprocessor to handle the processing, whereas a "Dumb Terminal" simply handles data input and output, and lacks the so-called intelligence capabilities.{ TERMINAL EMULATION A mode when your PC performs as if it were a terminal, such as the DEC VT100. TERMINAL MODE When a communications program is in terminal mode, it is behaving as if it were a computer terminal. Typed characters are passed on to the host system, and host characters are echoed to the screen. (See COMMAND MODE) TEXT A collection of printable characters.$ O TRANSMISSION RATE (See BITS PER SECOND)w TTY Short for Teletype. Also known as a dumb terminal. When a communications program is emulating a TTY, all received characters are displayed on the screen (in other modes, certain characters tell the terminal to position the cursor, clear the screen, and so on).aironment pBK- URNK131 TURNAROUND CHARACTER In half-duplex communications, this is the character the sending system uses to tell the receiver it is done sending. The two then reverse roles until the new sender transmits a turnaround. PTUTOR SYNTAX Whenever syntax is referenced the following terms are used to define the syntax format for that command:% P d - indicates a logical drive, which may be any drive on the computer system' [function] - this is the command name [argument] - this is an option (a variable or switch), that may consist of more than one argument, which determines or regulates the way the command will function. Enter - this terminates the command  [filename] - the name of the file& [.ext] - the extension name for the filek UART An Integrated Circuit within a computer which handles the interface between computer and modem. The UART translates the framing and data bits received by the modem into characters for the computer, and also does the reverse for transmitted characters.| UPLOAD Sending data (typically a file) to a host system. This is usuallyUis p疏K=  5 K132done by means of an error checking protocol. (See PROTOCOL) O USER The person at the local end of a connection with an online system orBulletin Board System. A user has a specific ID and password which identify him uniquely from all other users of the system. O USER MANUAL The manual that contains operational information, such as how to use the product (turn it on, start it up, etc), usually basic in nature and not extremely detailed or technical. It can be the same thing as Operations Manual or Operations Guide, depending upon preference of the manufacturer. This manual is provided with the purchase of the product. O UTILITY FILE A program used to assist in the operation of a computer, suchas SORT and CHKDSK. Utilities are usually classified by their purpose and usage, such as working with a hard disk or a printer. O VDT (Video Display Terminal) The display is used on the computer system to provide a means of input and output for the system.l VIDEO Signals made up of picture-producing elements that are used to display characters or graphics on a CRT.w VIDEO MONITOR Generally referred to as the Video Display which displaysWe PROTOCOL) p83210KE 7= 8133text K133text and graphics. A monitor has no intelligence, and requires a special controller card, called a Display adapter. Video Monitors are generally classified as monochrome or color.- O WARM START To reinitialize a computer system by pushing the reset button or by holding down the [Ctrl] and [Alt] keys while pressing the [Del] key. Sometimes called WARM BOOT.4 O WINDOW An area of a screen that displays information. Some programs support several windows that can be viewed simultaneously or sequentially.U WORD A set of characters that occupies one storage location and is recognized by the computer circuits as a unit. Word lengths are fixed orvariable, depending on the particular computer. O WORD DATA A number of bits that is treated by the computer as a unit andoccupies 1 storage location. In personal computers words are typically 4,8, 16 or 32 bits long.9 O WXMODEM (Windowed-XMODEM) An extension to the XMODEM protocol. Not widely used. XMODEM The grandfather of PC file-transfer protocols. Also known as theV special p/.֕ҕѕЕϕGLOSS END K-;+DEMK134MODEM protocol or Christensen protocol (after its inventor, Ward Christensen). Although it provides neither great speed nor great error detection, XMODEM's simplicity and ease of implementation have made it byfar the most widely implemented PC protocol. Variations include XMODEM-1K, XMODEM-CRC, WXMODEM, and YMODEM. (See WXMODEM, YMODEM, ZMODEM, CRC, CHECKSUM, BLOCK, PROTOCOL)5 PXON/XOFF A simple means of software flow control. During data transmission, if the receiving system needs time to process the data it has received or perform some other task, it sends an XOFF (ASCII 19, Control-S). The sending end will stop sending data until the receiver sends an XON (ASCII 17, Control-Q).9 O YMODEM An extension to the XMODEM protocol using CRC error-checking, 1024-byte blocks, and an extra block at the beginning of the transfer which contains the file's name, actual size, and date. O ZMODEM Rapidly becoming the most popular file-transfer protocol in the PC community. ZMODEM offers faster transfers with better error checking, greater reliability, restarting of aborted or interrupted uploads and downloads, and other advanced features. inventor, W pΕ͕ACK RNNNMMMMMMMMMMMMMMMMM>pS˻̼͹ͼ135ȹ ͼNNNNNNNNNNNNNNNNNNNN̻LɹLʼ pCredits `.`4``f(k`2`2`2`2`4``.`˻.˻.˻.μ Graphics, Software and Copy Produced by: 0  John C. Dvorak  &  Nick Anis, Jr. .λ.ʼ@ (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914  pyxcredits end new b*0%*0$*0$*YPRb+ % PRESS "ESC" TO EXIT "HOME" TO RESTART %+ % % ;HGIK D  pwvpdb_^quit ? new P*0%"00 *0 * C 4 C C C C C C C C C C C C? C Q% Arb+ % Are you sure you want to EXIT? %+ %  Cp]\) credits help ? '> >> 0>0>>>>01>0>>0100>>'>`.`4``kkfkf(kfkf``3`3`3`3`4``.`P6p 6p6p6p 6p 6p 6p6 L P Q H E L P #ͻ 1 OF 4  Press ESC to Exit Help   PgDn or F1 for Additional HELP  #ͼ  ˻.˻ .μ  Graphics, Software and Copy Produced by:  0 John C. Dvorak    &   Nick Anis, Jr. .λ ʼ. ʼ 6Q  F1 = HELP HOME = RESTART SHOW  UP = PREVIOUS SLIDE END = END OF SHOW  DOWN = NEXT SLIDE ESC = MENU/QUIT   F10 = MENU SLIDE BKSP = PAUSE SHOW   R = RESET  F9 = SET SPEED  8  6  9 (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914   NickHID op credits help2 ? '>  >> 0>0>>>>0>0>0>>'>UP Q H E L P #ͻ 2 OF 4 Press ESC to Exit Help   PgDn or PgUp for Additional HELP  #ͼ  ͻ KEYS  MAIN MENU SLIDE MOVEMENT SPEED MENU  MISC. ͹ F1 GET HELP GET HELP SPEED HELP A-M B&W ON F10 MAIN MENU MAIN MENU N/A A-C COLOR ON ESC QUIT MAIN MENU MAIN MENU S SET SPEED HOME FIRST CHOICE FIRST CHOICE FIRST CHOICE F9 SET SPEED PGUP FIRST CHOICE PREV. SLIDE FIRST CHOICE R RESET END LAST CHOICE LAST SLIDE LAST CHOICE A-T RESET TIME PGDN LAST CHOICE NEXT SLIDE LAST CHOICE 1-9 SET SPEED UP  PREV. CHOICE PREV. SLIDE PREV. CHOICE  S-TAB PREV. CHOICE PREV. SLIDE PREV. CHOICE  SPACE NEXT CHOICE NEXT SLIDE NEXT CHOICE A-L Logon User TAB/DOWN NEXT CHOICE NEXT SLIDE NEXT CHOICE ^Y Erase Line RIGHT OTHER COLUMN NEXT SLIDE NEXT CHOICE  LEFT OTHER COLUMN PREV. SLIDE PREV. CHOICE  DOWN NEXT CHOICE NEXT SLIDE NEXT CHOICE  ENTER MAKE CHOICE N/A  MAKE CHOICE  ͼ (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914 IHKD KpN@:status help     e'>)>> 0>0>>)>>0>0>0>>"f&>3fU0UD.D3,3 "* " (  (  ") "3,3D.DU0Uf2f NͻH E L P  #ͻ 3 OF 4  Press ESC to Exit Help  PgDn or PgUp for Additional HELP   #ͼ   ͻ AVAILABLE RAM:    Ķ  CPU SPEED (PC=10):     Ķ Ŀ VIDEO TYPE: Ŀ  ĴSystem  ĶSystemĿ ONLINE - MINS.:   Ŀ  Ķ  ĴStatus SERIAL #: Status  Ķ DISPLAY SPEED (0-9):    Ķ VERSION: 2.01  Ķ ¿  ٺ  "λ ȼ  ȼNͼ @ ~ }U@V XV |XV {XV zXV} |XV yX]uAp͓credits help 3 ?#'>)>> 0>0>>)>>0>0>>)'>iy;y y@py y@py yAqpy yAqyy yAqpy yAtyy ppAtpp Bqp yBqy yAtyy yAtyy yBpyy@pyEpE  0 Q H E L P #ͻ  4 OF 4  Press ESC to Exit Help "  Press PGUP for Previous Screen " #ͼ  / E   . THIS PROGRAM WORKS WITH JUST ABOUT ANY IBM COMPATIBLE SYSTEM,   FOR BEST RESULTS WE RECOMMEND AN AT COMPATIBLE EGA SYSTEM!   . The program performs best on a hard disk system. Disk access  occurs only two times, 1 - startup, 2 - switching to left or   right menu.6   . The "auto-progress" speed for slides can be controlled by the   slide speed menu. ("F9" or "S")"   . If your PC's clock is correct, the program menu will display   the date and time.< . While you use the program, your "Online" time is monitored and displayed on the menu, similar to modem connections. . To aid you in proper cursor control, on startup, the program  sets your NumLock off.8 . 's will appear for menu items you have already chosen. ] 7 9 (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914 TS WE RECOIHKD Jp|pm;:speed menu  xw*0&*0$*0$*0')l<:0:0<:::::9:::< P E E Dj S P E E D M E N U  ( !You can control the time delay between "each screen by choosing the rate below: :ͻ   SHORTREGULAR MEDIUM LARGE RATE SCREENS SCREENSSCREENSSCREENS :͹  FAST RATE (1) 1 4 8 10 FAST RATE (2) 1 7 16 20  FAST RATE (3) 2 11 23 30 MEDIUM RATE (4) 2 14 31 40 MEDIUM RATE (5) 3 18 39 50 MEDIUM RATE (6) 3 21 47 60 SLOW RATE (7) 4 25 54 70 SLOW RATE (8) 4 28 55 80 SLOW RATE (9) 5 32 62 90 :ͼ P (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914 ARGE;, IGOQ123456789K_v_vH_v _u _uP_uM_u      t s  r q"Yop98SPEED HELP b)0')0 )0')q`.`4``kkfkf(kfkf``3`3`3`3`4``.`#$1$$1$1$1$1$1$1$$  S P E EJ  S P E E D4  H E L P PRESS ANYKEY TO EXIT THIS HELP SCREEN!  3 $ ,! / ˻.˻ .μ  Graphics, Software and Copy Produced by:  0   John C. Dvorak   &   Nick Anis, Jr.  .λ ʼ. ʼ 9 $ ENTER = RECORD CHANGES " ESC = CANCEL, RETURN TO MENU ! UP = UP ONE LINE   DOWN = DOWN ONE LINE   R = RESET TO DEFAULT SPEED   - " 7 9 (c) Copyright 1989, Nick Anis, Jr., Computer Business Services, (714) 860-6914  opŒĒMenu#2 code 0 0J^1^P^/^ P^/^9> Loading Slides. @Please Wait. -/Qp&YU2VQVQVnQVQVRQVPQVOQVNQVQVMQVQVLQ]pҒInsert Disk#2 >2>2>22>6>>2/--- Please Insert Disk#2z 6 Press Any Key When Ready   2 pBAD SERIAL NO &*&*"*&**&*!**&*& *ͼ ͹*Sorry. You must have the file *  * MTSTART.DAT  * *in the current directory to*operate this program. *ͻ ͹* ͼ tvoopwvuGLOSS OVERLAY QNNNNNNNNNNNNNNNNNNNNNNNQNNͻNNNNNNNNNNNNNNNNNNNNNNNNͼ ptsL5. FNAME =n?n<n>n;n:n9nRL!N (NN2 ?2 2 2 22 2 3LR˻̼LȹL˻̼Lȹ Dvorak's Guide"M  To PC Telecommunications and Modem Tutor D USER REGISTRATION:Nͻ First Name:  ͹ Last Name:  ͹ Company:  ͹ Address: ͹ City, State, Zip:͹ Day Phone: ͹Evening Phone: ͼ̻ 92.01 ɹLʼ: m"=9Y`=1=U?T>\<[;Z:Y9Y._V_V=S<Wuv="4Y _mP_mQ_m _mM_ml=up LASTNAME =n?n<n;n>n:n9n?+m"?9Y`??"4Y _mP_mQ_m _mM_mHIKl?upߑّܑёCOMPANY =n?n<n;n:n>n9n}?O tO}>>"4Y QP MHIKl>upADDRESS =n?n<n>n;n:n9n)?\z\?m"<9Y`<< _mP_mQ_m _mM_mHIK"4Yl<upkjCITY STATE =n?n<n>n;n:n9ng?Dm";9Y`;;"4Y _mP_mQ_m _mM_mHIKl;upihfc[BADAY PHONE =n?n<n>n;n:n9n ??m":9Y`:: _mP_mQ_m _mM_mHIK"4Yl:up@?<91EVEN PHONE =n?n<n>n;n:n9nSU?ee rm"99Y`99 _mP_mQ_m _mM_mHIK"4Yl9upϐΐupdateing =n?n<n>n;n:n9n^:^ _U_UU^_UU:^_UU:^UU;4 ; Updating "  your ; User Profile > ; eIl&Yp=p?p>p<p;p9p:HkH=GkG?FjF>EjE<DjD;CjC:BjB9&Y4vip͐̐ÐERROR MESSAGE 9n:n;n>n<n=n?nD^8^_UU7^_UU5^_UU6^UU:QD 9 This information : is required to 6 use the program.: : eThvtp:KK2 ppsppp  2(22"1191YY`v $Y`u (Y` 2$22"1191YY`"1191Y`"1191Y`+w*w)w(w'w&w%w$w#w"w!w wwwwwwwwwwwwww`}ii bg b |} `::feZwZ`dcbcacacdcacbw`Ip&YH=G?F>E<D;C:B9o=o?o>o<o;o:o9&Y`Vt=?><;:9`