Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 31 mm224.t Multitech MultiModem 224 without MNP. This dialer supports many 2400 bps modems with little or no modification. mm224e.t Multitech MultiModem 224E with MNP. mmv32.t Multitech MultiModem V32 with MNP. sm1200.t Hayes Smartmodem 1200 tb.t Telebit TrialBlazer Selecting the proper modem type takes two steps. First the file name for the desired dialer must be specified in your DOS (or Unix) environment. NB. The following must be entered without extra spaces. EXAMPLE: C>set MODEM=mm224e.t (DOS) EXAMPLE: $ MODEM=mm224e.t; export MODEM (Unix) Second, the Zcomm lib string variable must be set in the setup phone directory entry or in phones.ts. EXAMPLE: set lib "C:/ZCOMM" (DOS) EXAMPLE: set lib "/usr/lib/yam" (Unix default) When setting up for a particular modem type, be sure to configure the modem's switches and Non Volatile RAM (NVRAM) for use with ZCOMM. If nonstandard NVRAM settings interfere with ZCOMM's initialization scrip for that modem, you may have to manually restore the NVRAM contents to the factory default. The supplied scripts expect to see the factory default VERBAL RESULT CODES (not result digits). The adial dialing script supports a number of modems under control of the MODEM environment variable. 9.3 New and Improved Modems Modem manufacturers are constantly refining their products, adding new features and making subtle subtle changes in existing features. To obtain the full performance your modem provides, you can edit initialization strings in the dialing scripts to take advantage of new modem features as they are developed. (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 32 If your modem is not listed in one of the following subchapters, please read all the subchapters and use the suggestions that apply to modems similar to yours. 9.4 Pulse Dialing If your telephone line requires rotary (pulse) dialing, set mprefix to ATDP with a command in the setup telephone directory entry. This procedure is detailed in Chapter 8. 9.5 MNP, V.42, X.PC, AFT More and more modems support one or more error correcting link level protocols such as MNP and V.42. Modem to modem link level protocols correct most transmission errors reducing the frequency of garbled text and file transfer retries. Modern link level protocols increase transmission speed by eliminating start/stop bits and redundant information. When MNP is enabled, the calling modem sends control characters to interrogate the answering modem for MNP. These characters can prevent logging in to some timesharing systems, packet switched networks, and bulletin boards. Non streaming protocols such as XMODEM, YMODEM, and Kermit usually give faster transfers without the delays introduced by MNP and other link level protocols. Accordingly, ZCOMM's dialing scripts are designed to place calls with MNP disabled by default. No modifier is used for AFT, V.42, or V.42bis link protocols. We have not experienced log-in or throughput problems with these protocols, so we made them the default. The dialer scripts support one or more of the following modifiers: /300 Force a connection at 300 bps. Dropping down to 300 bps may be necessary to get a reliable connection in the Oregon Rain Forest. /1200 Force a connection at 1200 bps. /2400 Force a 2400 bps connection. /nop Suppress the detection of call progress reporting. This may be used to prevent the modem from misinterpreting an unusual ringing sound as a busy signal. /fast Force a high speed connection (refuse a slow speed connection). EXAMPLE: 123-4567/fast (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 33 /man Some modems incorrectly abandon a call attempt when they "hear" sounds they aren't programmed to understand. For example, some TrailBlazer modems abort the call with a spurious "NO CARRIER" message when they hear the sound of the telephone "ringing". If that doesn't dump the call, the TrailBlazer may dump the call when the answering modem emits an echo suppressor disabling tone before sending the standard Bell 103 answer tone. Under these circumstances the only solution is to listen to the sounds yourself and tell the modem exactly when to start listening. With the man modifier, the modem remains in command mode after dialing the phone number and ZCOMM enters the term function to display messages from the modem. When you hear the called modem's answer tone, hit F1 to exit the term function. The dialing script then sends an "ATO" to the modem to attempt a normal data connection. Some practice may be necessary before you get the right timing. If you hit F1 too late the answering modem may timeout before the modems can handshake and enter data mode. mnp Require MNP link level connection. Do not connect if MNP fails. EXAMPLE: 123-4567/mnp /mnp_s Require MNP link level connection, use software flow control.[1] Do not connect if MNP fails. /a_mnp Request MNP link level connection. /a_mnp_s Request MNP link level connection, use software flow control. /xmodem Enable "XMODEM spoofing" on Trailblazer modems. /kermit Enable "Kermit spoofing" on Trailblazer modems. /v22 Use V.22 modulation (effective for 1200 bps calls). /c:modifier Optional modem dependent modifier string __________ 1. Software flow control in the modem is not compatible with XMODEM, YMODEM, Sealink, Clink, or WXMODEM. (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 34 9.6 High Speed Modems The new generation of high speed dial-up modems presents special challenges to users and system integrators. These modems transmit data at speeds from 110 to 38400 or more bits per second. This range of speeds poses special problems communicating between the computer and the modem. Lower speed modems examine the traditional "AT" command prefix bit by bit to lock onto the computer's transmission speed instantly. Many modems which recognize commands at widely varying speeds can not use this technique. A number of alternate techniques have been developed, each with its own advantages and problems. + Lock the interface to the highest transmission rate. This avoids the programming required to synchronize the modem's and computer's speeds. Flow control must be used when the interface speed is locked to prevent the computer from sending data more rapidly than the modem can buffer and transmit it. This local flow control is usually accomplished with hardware signals. When such an arrangement is used to communicate over networks that must assert their own flow control (with XON and XOFF), data flow regulation must respond to both hardware (RTS) and software (XOFF) signals. The handshake both command should be used whenever the modem's interface speed is locked and transmission over networks or to timesharing systems is desired. Locking the interface speed to 9600 or 19200 bps while communicating at 1200 and 2400 bps should be avoided unless all links in the transmission path have low error rates. Most modems do not recognize XOFF characters from the remote computer, so characters stored in the modem's buffer will be transmitted for a period of time after an XOFF is received. This causes loss of data with some computer services. When the interface speed is locked at a higher speed than the actual data transmission, an excessive amount of data may be stored in the modem's memory awaiting transmission. This is inefficient when a streaming file transfer protocol is used because the data stored in the buffer must be drained before error recovery can commence. The ZMODEM b and w numeric parameters should be used to manage the modem's data storage. + Autobaud to adjust the modem and computer speed. With this method, the modem is optioned to enter a search mode whenever it becomes idle. The dialing script calls the waketb phone directory subroutine to train the modem to the computer's transmission speed. The waketb subroutine may be optimized for the particular modem used. (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 35 After dialing or answering a call, the modem handshakes with the remote modem and reports the connect speed with a message such as "CONNECT 1200" or "CONNECT FAST". The dialing script recognizes the string, and sets the computer to the correct speed. If the connection is made at high speed, the dialing script may need to enable hardware flow control with a handshake command. 9.7 Line Sharing with FAX Machines Sometimes you can share a dial-in line between a modem and FAX machine without extra hardware. Many modems have both line and phone jacks, and they disable the phone jack when the modem is online. Connect the modem to the line and connect the FAX machine to the modem's phone jack. Next, determine how many rings the FAX machine requires before answering the phone and set the modem to the same value with the modem's S0 register. Set the modem carrier detect time limit to 18 seconds with the modem's S7 register. When the phone rings, both the FAX machine and modem try to pick up the phone line, but the modem disconnects the FAX machine from the line while it attempts to handshake. If the incoming call is for the modem, the FAX machine will time out after about a minute. If the call is for the FAX machine, the modem will reconnect the FAX to the phone line after its 18 second timeout. Your results may vary depending on the type of modem and FAX machine you use. EXAMPLE: call init,aa initializes a MultiTech modem to answer on the second ring. 9.8 TELEBIT TrailBlazer The Telebit TrailBlazer modem uses 68000 and TMS320 processors to transmit serial data at rates up to 14000 bps over standard phone lines. The modems also operate at speeds of 2400, 1200, 300 and slower. The TrailBlazer is one of the most complex modems to fully exploit, a worthy challenge for a TurboDialTm script. Set the MODEM environment variable to tb.t to support the TrailBlazer's MNP, speed and flow control features. Before making calls, use the init phone entry to initialize the modem's non volatile memory with proper settings for ZCOMM. EXAMPLE: call init Telebit modems feature protocol spoofing to increase the performance of traditional file transfer protocols such as XMODEM, Kermit and (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 36 UUCP. This spoofing interferes with other protocols, slowing or preventing file transfers. ZMODEM provides optimum file transfer speeds with these modems. ZMODEM avoids interference with the modem's flow control. This posting is intended for those who use Pro-Yam for access to Xenix/Vpix with wyse 60 terminal emulation mode. These modem register settings are in use on a Telebit T1000 calling a Telebit trailblazer modem. The host modem has register 58=3 (xon/xoff). While these may not be the optimal settings.. they work !!. E1 F1 M1 Q0 T V1 W0 X1 Y0 &P0 &T4 Version FA2.00 S00:010 S01=000 S02=043 S03=013 S04=010 S05=008 S06=002 S07:045 S08=002 S09=006 S10=007 S11=070 S12=050 S18=000 S25=005 S38:020 S41=000 S45:255 S47=004 S48:001 S49=000 S50=000 S51=255 S52:002 S54:003 S55=000 S56=017 S57=019 S58:002 S59=000 S60=000 S61=150 S62=003 S63=001 S64=000 S65=000 S66=000 S67=000 S68=255 S69=000 S90=000 S91=000 S92:001 S94=001 S95:002 S96=001 S100=000 S101=000 S104=000 S111=255 S112=001 S121=000 S130:000 S131:001 S255=001 Courtesy Dr. Adam Orden 9.9 MultiTech MultiModem V32 This modem adds 9600 bps V.32 to the MM224e. 9.10 MultiTech MultiModem 224E Set the MODEM environment variable to mm224e.t to support the MM224E's MNP, speed and flow control features. Set dip switch 1 on the bottom of the modem to up (DTR Normal), the reverse of the factory setting. For high speed operation, CTS flow control should be enabled with internal switches and jumpers. Before making calls, use the init phone entry[2] to initialize the modem's non volatile memory with proper settings for ZCOMM. EXAMPLE: call init This disables automatic error correction under mnp. If you wish to enable this setting by default, merely type, from the terminal mode, 'AT &E1 &W', and the 'OK' which will ensue tells you that the command was accepted and stored in non-volatile memory. The init script also disables MNP compression. MNP compression slows transfers of compressed files. If you do not transfer many compressed files, change the &E14 in the init script to &E15. __________ 2. Information courtesy Earle Robinson (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 37 9.11 MultiTech MultiModem 224 Set the MODEM environment variable to mm224.t to support the MM224. 9.12 U.S. Robotics Courier 2400e Unlike most medium and high speed modems, the Courier 2400e does not recognize the computer's transmission speed when given "AT" commands. Set the MODEM environment variable to c2400e.t to support the C2400E. This modem should be initialized with the init entry in the telephone directory. Switch settings are off, off, on, off, on, off, off, on, on, off. 9.13 U S Robotics HST Dual Standard The init phone directory entry should be run to initialize the HST properly. The HST firmware design requires the MNP DTE speed set in the first script line of hst.t to match the speed used in initmodem If you wish to change the interface speed, the speed must be changed in both places. When making MNP calls to CompuServe and certain other modems, a /2400 modifier may be required with some HST firmware versions to correct a MNP4 compatibility problem. EXAMPLE: compuserve speed 2400 123-4567/mnp/2400 9.14 Hayes Ultra Smartmodem 9600 Set the MODEM environment variable to hu96.t to support the modem's MNP and flow control features. This modem should be initialized with the init entry in the telephone directory. The V.42 link level error control is enabled by default because it does not appear to interfere with connections to modems not supporting V.42. 9.15 Hayes Smartmodem V9600 This modem should be initialized with the init entry in the telephone directory. The AFT link level is enabled by default because it does not appear to interfere with connections to modems not supporting AFT. (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 38 9.16 Hayes Smartmodem 2400 The Hayes Smartmodem 2400 presents the same considerations as the Smartmodem 1200 described below. Unlike the 1200, the 2400 uses a non volatile memory to store configuration parameters instead of the switches used in earlier models. The sequence AT&C1 &D2 &R1 &S1 &T5 &W should be sent to the modem to set normal operation for DCD, DTR, CTS, and DSR. The T5 command disables remote loopback request, a source of failed file transfers on noisy lines. Finally, the &W command writes this information to the non volatile memory. Please consult your Hayes manual for more information on these commands. 9.17 Hayes Smartmodem 1200 Set the MODEM environment variable to sm1200.t to support the Smartmodem 1200 and similar 1200 bps modems. Some modems may require a change in the X1 command to a higher Xn digit for proper autobaud operation. The Smartmodem 1200(TM) should be configured as follows by setting S1-S8, located under the front panel. These switches may be accessed by gently prying the ears of the front bezel, allowing the bezel to pop off the front of the unit. S1 Up Support DTR Lead S2 Up Verbal result codes (Verbose) [3] S3 Down Result codes are sent S4 Up Echoes characters in command state S5 Down Modem does not answer calls initially S6 Up Carrier Detect line reads status S7 ???? See Hayes manual S8 Down Enables Smartmodem 1200 command recognition The modem cable should connect the following RS-232 circuits: AA BA BB AB CF CD which use pins 1,2,3,7,8, and 20 on the Hayes modem. Some programs require pins 5 and 6 connected to the modem. NOTE: Some Hayes modems require mprefix to be in upper case only. "Hayes Compatible" modems not manufactured by Hayes generally work with the same mprefix, but some of the other modem control strings that appear in the distributed PHODIR.t file may not work properly with a particular brand of modem. __________ 3. If other options are necessary (to support other software) a custom dial routine may be used as described in Chapter 99. (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 39 9.18 Microcom AX9624c Microcom AX modems have a configuration switch to select Hayes style "AT" commands. The AX/9624c front dip switch should be set 1, 4, 6, 7 UP, 2, 3, 5, 8 DOWN, and A/S OUT (asynchronous). The rear switches are all UP. Of all these switches, it is vital that front switch 2 be DOWN (AT commands) and rear switch 6 be UP; the init script should override the others. Set the MODEM environment variable to ax9624.t to support the Microcom AX9624's MNP and flow control features. Before making calls, use the init phone entry to initialize the modem's non volatile memory with proper settings for ZCOMM. EXAMPLE: call init 9.19 Microcom SX Series Older Microcom SX series modems have a unique command set incompatible with Hayes modems. Careful attention must be paid to flow control issues to obtain reliable operation. When using XMODEM or other protocols, the modem must be set to pass all 8 bits and all 256 code combinations of those 8 bits. The dialsx script sets the modem to "transparent software flow control" as described in Chapter 14. Change the line set mcommand "gosub dial" to set mcommand "gosub dialsx" in the setup telephone directory entry. 9.20 Prometheus ProModem 1200 The following switch setting works with ZCOMM: 1-4,6,9 on; 5,7,8,10 off.[4] A custom "dial" script can be written to operate this modem in its native mode. __________ 4. Prometheus mode does not work with ZCOMM's built-in dialing software because the "DIAL COMPLETED" message makes ZCOMM think it's seen "CONNECT" (ZCOMM looks for a "T"). (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 40 9.21 Standard 103/212 The supplied "dial" script will present the number to the user and wait for a success/fail response if the mprefix string parameter is set empty. Alternatively, one could change the script to loop waiting for carrier detect while the keyboard is inactive. The Data Set Ready (DSR) signal may be connected to the modem's speed detect output (high for 1200 bps, low for 300) allowing the dr test condition to sample the DSR line to determine the speed of the incoming call. 9.22 Data Race BMX These modems have a switch selected interface speed, an AT style command set, and switch options for software or hardware flow control. Recommended settings are: AT commands, Dialup, 8 bit data (down), disable XON (7 and 8 down), Echo on. ZCOMM's handshake on command should be used. 9.23 Strange Modems Most intelligent modems can be commanded to autodial with a suitable mprefix and msuffix string. Those modems that won't work with a particular mprefix can be programmed with a custom "dial" script. If the modem can be configured to reset to a known condition when DTR is turned off, programming is usually straightforward. Otherwise, the script must determine what speed the modem is set to, and then, at its present speed, command the modem to change to the desired speed. The essential requirement is to write a script that controls the modem and responds to its state. The information on scripts in Chapter 99 should prove useful. 9.24 Manual Dialing with Smart Modems Some hotels and exotic locales sport telephone systems with unusual dialing requirements. It may be necessary to dial the call with the telephone, talk to an operator, and then activate the modem. With Hayes compatible modems, an ATD command may be given to the modem to connect it to the line and attempt a data handshake. 9.25 Direct Connection ZCOMM works well communicating with locally connected microcomputers, minicomputers, or mainframes with direct RS-232 connections. For such applications, only transmit and receive data data lines need be connected to the computer. The Carrier Detect line[5] should be (C) 1990 Omen Tech Inc Chapter 9 Unleashing the MODEM Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 41 driven ON (+5 volts) to prevent noise on this line by strapping it to Data Terminal Ready [6] if no other signal is available. For best high speed operation, replace 8250 or 16450 UART chips with the NS16550AN chip. ZCOMM enables the hardware buffering on this chip to avoid data loss caused by TSR programs, special device drivers, extended memory disks or caches, and DOS clock interrupts. ______________________________________________________________________ 5. Pin 8 on 25 pin RS-232 connector, pin 1 on PC-AT 9 pin connector. 6. Pin 20 on RS-232 connector, pin 4 on PC-AT 9 pin connector. (C) 1990 Omen Tech Inc Chapter 9 Tutorial Introduction Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 42 10. HANDS ON TUTORIAL As a first order of business, run the demonstration program by typing ZCOMMDEMO at the DOS prompt. The demo asks certain questions about your system, and then allows you to exercise a few of ZCOMM's features from a menu. It's a good way to get a first "feel" for ZCOMM before getting down to business with the industrial strength software you will be using. Remember to turn off the CAPS LOCK key when running ZCOMM. ASSUMPTIONS: In addition to the minimum hardware requirements for ZCOMM, this tutorial assumes the use of a Hayes Smartmodem 1200 (or equivalent) connected to the COM1 port in accordance with the instructions in Chapter 9. The tutorial assumes that ZCOMM.EXE, YHP.EXE, UMANH.HLP, and PHODIR.t are copied to the root directory of your working disk, and that ZCOMM.EXE has been serialized with the putsnp program. If your system configuration is different, you will have to read the manual carefully to learn how to adjust for your configuration. After typing ZCOMM from the DOS prompt to load ZCOMM, type F10 to activate the flash-up help processor. Browse through it to familiarize yourself with the information available via the F10 (help) key. To make a call without using a directory entry, type speed 1200 (or whatever) and then the phone number: speed 1200 123-4567 The modem then dials the number. When you are connected, ZCOMM will return to its command prompt. Keyboard F2 to begin talking with the remote. Give some commands to the remote until several screens' worth of text have scrolled by. Now press the PgUp function key. The screen will now display text that had scrolled off before. Use the PgUp, Home, PgDn, and End function keys to move around in the review buffer. Look for a moderately interesting nugget of wisdom, and use the up arrow and down arrow function keys on the numeric keypad to place the interesting part at the top of the screen. Hit "t" to set the top marker. This causes all the text to display in high intensity. Now move down using the down arrow key to place the first line of unwanted text at the top of the screen. Hit the "b" key to set the bottom pointer. This will change the displayed text back to normal intensity. (C) 1990 Omen Tech Inc Chapter 10 Tutorial Introduction Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 43 Now hit "w" and ZCOMM will prompt for a filename to write to. Type the filename followed by , and ZCOMM will write the selected data. When the write operation is finished, the screen will redisplay the text. When you have the feel of it, type F1 to return to the term function and conversational connection to the remote computer. The demonstration disk circular buffer search/cut/paste menu choice demonstrates many of the review subcommands. Next, log off the remote computer. When it drops the line, ZCOMM displays No Carrier Detect in reverse video to announce that the connection has been lost. At this time you are still in the term function. Hit F1 to return to ZCOMM's command prompt. Then type "off" to disconnect the modem and exit back to the operating system. Now is a good time to read the rest of the manual to discover the power of ZCOMM. Chapter 10 presents some unusual sessions demonstrating more of ZCOMM's capabilities. 10.1 Sample Sessions Direct connection to COM2 at 19kb unix port 2 speed 19200 source 101.mk; t | | | | | | | Map keyboard, Invoke term function | | ___ Set 19200 bits per second | ______________ Select port COM2 _________________________ System name Typical bulletin board rcpm port 1 speed 1200 123-4567 t -8g | | | | | | | | | _ Term function, graphics | | | _______ Number to call | | __________________ 1200 baud | _________________________ Select COM1 ____________________________________ System name A Not so Typical Session The example below assumes a Hayes modem connected to a radio receiver tuned to the W1AW ASCII bulletins. Refer to a recent issue of QST Magazine for a W1AW schedule. to select the best signal. Usually, the error rate is lowest when receiving a strong signal near the Maximum Useable Frequency (MUF). Set the radio for Upper Sideband (C) 1990 Omen Tech Inc Chapter 10 Sample Sessions Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 44 (USB) reception. Tune it so the resulting audio frequencies make the RD (Received Data) light turn on about 50 percent of the time. Reset the modem by powering it down before attempting regular calls. w1aw speed 110 putw "ATS10=255 C0 H2 D\r" t -v | | | | | -v prints control chars | | as ^C so they won't | | erase the screen, etc. | Ignore Carrier Detect, Carrier Off, Special Off | Hook (Don't close relay), Originate, Online |________ W1AW ASCII transmissions are at 110 bps A>ZCOMM call unix Connect to a local system named unix jabber jabber ... Login to system, change directory Command: Get a ZCOMM command prompt sz prg?.? prghlp.mm Upload some files jabber jabber ... sz *.c *.h Download some source files Receiving ... ZMODEM AutoDownload accepts them kermit -ix Start the Unix Kermit server >>>c: Get ZCOMM's command prompt remote dir Get a directory listing Directory... Directory listing on screen get f2 Get (fetch) a file f2 Open ... File arrives send myfile Send myfile to server finish Finish server access t Enter term function kermit send f1 Start a Kermit file transfer f1 Open... File is received AUTOMAGICALLY! jabber jabber ... Log off local system >>>c: Get ZCOMM's command prompt port 1 Select modem on COM1 call rcpm Dial a system called "rcpm" jabber jabber ... Keyboarding with remote Review function at top of text /to superhacker Search for beginning of message to you t Set top pointer /to j. fred muggs Search for beginning of next message b Set bottom pointer w Write selected text to a disk file Return to term function E Tell the rcpm to enter a message Command: Get a ZCOMM command prompt open -pt letter Open "letter" and send to bbs, using prompt and throttle modes to slow transmission so the remote system won't drop characters. dir Find out what files are on the RCPM xmodem s foo.bqr Command RCPM to download a file (C) 1990 Omen Tech Inc Chapter 10 Sample Sessions Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 45 Command: Get a ZCOMM command prompt rc foo.bqr Download a file with XMODEM/CRC PgUp PgUp ... Flip back to the first part of directory previously listed Back to term function xmodem s dr.who Download a critical file Command: Get a ZCOMM command prompt rc \misc\dr.who Download the file jabber jabber ... More keyboarding, logoff >>>c: Get ZCOMM's command prompt Connect the modem to the radio's audio and tune in W1AW create rtty.tmp Create a disk file for the bulletins call w1aw bleep twort sneep Static on the radio - pure line hits until W1AW is received while sending ASCII k Review/k command clears the buffer QST DE W1AW ... END ... AR Close the capture file >>>c:off Return to DOS (C) 1990 Omen Tech Inc Chapter 10 Accessing Computer Systems Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 46 11. ACCESSING COMPUTER SYSTEMS 11.1 Dialing Once you modem is interfaced per Chapter 9, you can connect to a remote system with the call command referencing an entry in your telephone directory. EXAMPLE: call kgbvax If a telephone directory entry has not been set up, TurboLearn(TM) may be invoked to dial a phone number and then learn your login procedure by keyboarding the F4 key. You may choose to add the resulting script to your telephone directory, or retain it as a separate file acessible with the source command. Please refer to the learn command in Chapter 19. If you just want to call a number without ZCOMM learning anything, just type the telephone number from the command prompt already.[1] EXAMPLE: 123-4567 When the modem connects, ZCOMM returns to the command prompt. You can then keyboard the F2 key to connect your keyboard to the remote system. If you wish to use "bulletin board graphics", use t -8g instead. 11.2 Telenet/PC-Pursuit For best results, identify with D1 when Telenet asks for your terminal type. This selection prevents the network from adding padding characters, which are just a waste of time with ZCOMM. To use XMODEM, YMODEM, Telink, and other traditional protocols on PC Pursuit, type SET 1:0,4:2,5:0,7:8,12:0 after connecting to the PC-Pursuit target city. This command prevents Telenet from "eating" control characters or breaking the connection when files containing certain patterns are transmitted. This command disables Telenet's "@" escape. For ZMODEM or Sliding Windows Kermit a better alternatitive is: __________ 1. You may wish to add the /mnp modifier described in Chapter 9. (C) 1990 Omen Tech Inc Chapter 11 Accessing Computer Systems Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 47 SET 4:2,5:1,12:1 Please refer to Chapter 14 for network flow control considerations. 11.3 Tymnet If using Tymnet, type Ctrl-R Ctrl-X just before the host computer name to enable software flow control with XOFF and XON characters. "Half Duplex" may be activated with Ctrl-H. Check with your network's documentation for further details or updates to this information. (C) 1990 Omen Tech Inc Chapter 11 File Names Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 48 12. FILE NAMES Good and Bad The pathnames of downloaded files must be legal PC-DOS file names as described in The File Specification in chapter 2 of the PC-DOS manual. When choosing file names, remember that PC-DOS does not distinguish between uppercase and lowercase characters in pathnames. The Compuserve-B, ZMODEM, YMODEM, and Kermit protocols use pathnames generated by the sending program. File names transmitted from other systems may not be legal for DOS, or they may reference directories that cannot be created.[1] When ZCOMM receives a pathname from the sending program, ZCOMM first checks for the existence of a file with the same name. If no such file is found, ZCOMM attempts to open the named file for writing. If the file cannot be created because directories specified in the pathname do not exist, ZCOMM attempts to create the directories. A pathname that cannot be opened for reading or writing is considered illegal. EXAMPLE: foo..bar is illegal for DOS because it contains two dots. An Illegal pathname is translated to name.NNN where name is the filename portion of the given file name restricted to 8 characters, and NNN is an assigned three digit number starting with 001 and incremented after each file download. If a file with this new name already exists, the number is incremented up to 999, until a unique file name is found. The open fails if a unique number cannot be found. EXAMPLE: A downloaded file with the name newprog.patch.1 might actually be downloaded as newprog.001. This check for illegal file names is made whenever ZCOMM attempts to create an output file. EXAMPLE: t foo.bar.baz given from the command prompt would invoke file name translation. __________ 1. A cirectory cannot be created if a regular file with the same pathname is present. (C) 1990 Omen Tech Inc Chapter 12 File Names Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 49 12.1 Pathname Translations Files affected by the dirrx, dircx and dirpx string variables have their directory paths and/or device specifier stripped if the string variable ends in a "/". Otherwise a file specification with an absolute path overrides the string variable. The pathname of the incoming file is checked before any of these transformations, allowing a host system to place all files received with a protocol in a private directory. EXAMPLE: C>set DIRRX=C:/download places files received with a protocol in the download directory on drive C unless the file specification included an absolute path or device letter. dirrx File Stored Location (empty) any (same) C:/a f C:/a/f C:/a /f /f C:/a A:f A:f C:/a/ f C:/a/f C:/a/ /f C:/a/f C:/a/ A:f C:/a/f Parameter Affected commands dirrx r{bcotwx7}, fget, get, bdump, usq, ZMODEM/Kermit AutoDownload dirsx s{bctx7}, send, B protocol sends[2] dircx create, t, message, private, >, bro/a ap[d] (2nd argument) dirpx review/w dirfx f, open To show the possible pathname translations, consider the pathmame: A:/spy/kgb/sabotage/666 sent between two copies of ZCOMM with the ZMODEM protocol. The sending program command: sz A:/spy/kgb/sabotage/666 sends the file name 666. The command sz -f A:/spy/kgb/sabotage/666 sends the complete pathname /spy/kgb/sabotage/666. __________ 2. If the dirsx parameter is set, ambiguous or wild card file names cannot be used. (C) 1990 Omen Tech Inc Chapter 12 File Names Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 50 The command sz ONAME=hogwash A:/spy/kgb/sabotage/666 sends the pathname hogwash. sz PREFIX=C:/fbi/security/intelligence A:/spy/kgb/sabotage/666 sends the pathname C:/fbi/security/intelligence/666. Note that a disk identifier (C:) is being sent. On reception with ZMODEM AutoDownload or the rz command, the last example (C:/fbi/security/intelligence/666) would normally be stored under that exact pathname, creating the directories C:/fbi, C:/fbi/security, and C:/fbi/security/intelligence if needed. If the dirrx string variable had contained C:/downloads the incoming drive specifier would still have overidden the dirrx specification. If the dirrx string variable had contained C:/ollie/to_do/ the file would have ended up as C:/ollie/to_do/666 to the consternation of all. The command rz foobar could have been used to rename this file to foobar in the current directory. The oncloserx and onclosetx string parameters may be used to specify commands to execute after each file received or sent with file transfer protocols. Their use is described in Chapter 13. (C) 1990 Omen Tech Inc Chapter 12 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 51 13. PROTOCOL FILE TRANSFERS With many different ways to transfer files with ZCOMM, your choice of file transfer methods could make the difference between efficient, error free data and slow or error prone transfers. This chapter gives an overview of the different ways to transfer files with emphasis on their relative merits. A file transfer protocol should have high integrity (assurance of accurate data) and high robustness (low probability of aborting a transfer). The following subchapters discuss these file transfer methods in more detail. 13.1 ZMODEM-90 ZMODEM was developed for the public domain under contract by Telenet, a major packet switched network. ZMODEM-90(TM) is a refinement of ZMODEM with increased performance, reliability and compatibility with a wider variety of environments. ZMODEM provides a greatly simplified user interface. The file name is entered once, and transfer options may be given to the sending program, even those that apply to the receiver. ZMODEM AutoDownload(TM) allows menu and mouse driven programs to download files and commands with no extra keyboarding required. ZMODEM transfers one or more files with a single command. The size and transfer time for each file is displayed, and the total number of files, size, and transmission time is displayed when more than one file remains to be sent on a command. Keyboarding ALT-F allows the receiver to bypass an individual file without having to restart the batch. ZMODEM transfers both files and commands. Command download allows one of the computers to take positive control of the session. A security challenge (activated by ZMODEM AutoDownload(TM)) guards against Trojan Horse messages.* ZMODEM file transfers can preserve the file date and the exact file contents, unlike traditional protocols that append garbage to files. Streaming transmission provides full throughput over satellite links and packet switched networks. One of three ZMODEM streaming control methods may be used with systems that allow the sender to monitor the received data for error correction packets without interrupting transmission. ZMODEM's "block length" is the entire file! Individually acknowledged packets support other systems. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 52 ZMODEM allows programs to adjust the protocol parameters for optimum efficiency as the file is being sent. ZMODEM-90 allows programs to adjust character encoding for best results with a variety of systems. Some programs support ZMODEM compression for even faster file transfers under appropriate conditions with the Z file transfer option (q.v.). ZMODEM is immune to conditions that prevent reliable, accurate file transfers with traditional protocols: + ZMODEM data transfers are protected by the Federal Standard 32 bit CRC to assure reliable transfers. This 32 bit CRC gives an undetected error rate five orders of magnitude better than XMODEM's 16 bit CRC, and more than a billion times better than checksum XMODEM. ZMODEM uses 16 bit CRC for file transfers with programs that do not support 32 bit CRC. + Most important, all ZMODEM protocol transactions are protected by CRC. Other protocols advertising 16 or 32 bit CRC sometimes fail under stress because critical control messages are not CRC protected. If you've ever been disconnected when a huge file transfer was almost finished, you'll appreciate resuming/recovering the file transfer with ZMODEM Crash Recovery (ZMODEM r option.) Omen Technology Inc's Intelligent Crash Recovery(TM) guards against file corruption during Crash Recovery operations. You can use the ZMODEM n option to transfer only those files that have changed since the last time they were transferred. With the p option, you can unconditionally protect files that already exist on the destination system. To update only the files you already have while skipping the rest, use the Yn options. To send a file with ZMODEM, the command sz file1 can be given from either the main command prompt, or from the term function via a secondary command prompt obtained with ALT-2. Multiple files and wild cards may be used. EXAMPLE: sz file1 file2 *.lst 13.1.1 ZMODEM AutoDownload If Z mode has been enabled (the default), ZCOMM's term function will detect a ZMODEM transmission and receive the file(s) automatically, after a security check. File transfer options for ZMODEM automatic downloads may be specified with the adlopts string parameter. The rz command may be also given from a command prompt. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 53 Please refer to the sz and zcommand commands described in Chapter 19 for examples and information. Rz and sz programs for Unix and VAX/VMS are available in rzsz.zoo and rzsz.tlb. 13.1.2 Tuning ZMODEM Parameters Chapter 24.2 describes a number of ZMODEM numeric parameters which may be adjusted for extraordinary situations, or to fine tune the last 0.1 per cent of possible performance. The ZMODEM subpacket length (zmodem L parameter) and the ZMODEM frame length (zmodem l parameter) deserve special mention. People tend to confuse these with the familiar 128 and 1024 byte block length used in XMODEM transfers. When a ZMODEM frame length of 0 is specified (the default), a single frame will span the entire file if there are no errors. This is the main source of ZMODEM's reputation for fast transfers. Setting the ZMODEM frame length to a number between 64 and 16384 restricts the frame length to that value. At the end of each frame, the sender stops sending and waits for an acknowledgement from the receiver. When set, the ZMODEM frame length corresponds in function to the 128 or 1024 byte block length of XMODEM based protocols. Each ZMODEM frame consists of one or more subpackets of 32 to 1024 bytes. Since the subpackets within a frame are sent without pause, a short subpacket length does not exact the terrible throughput penalty associated with short XMODEM and Kermit blocks. In the absence of transmission errors, a 256 byte subpacket length has about two per cent more overhead than a 1024 byte subpacket length. However, the longer subpacket length does increase error recovery time. ZCOMM dynamically adjusts the ZMODEM subpacket length on the basis of transmission speed and observed error rate. If you know what the error rate on a particular call will be before starting a ZMODEM file transfer, setting the zmodem L numeric parameter will provide a small but noticeable improvement in performance, with 1024 best for clean lines and smaller numbers better for noisy lines. When sending files over noisy phone lines not involving networks, the speed of error recovery may be increased by decreasing the values of the ZMODEM t and p numeric parameters. Information about YMODEM and ZMODEM protocol internals is provided in ymodem.doc and zmodem.doc, part of Omen Technology's ZMODEM Developer's Collection. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 54 13.1.3 MobyTurbo Standard ZMODEM escapes network control characters. This causes a slight drop in throughput when sending compressed files. When transferring compressed files over circuits that pass all 256 8 bit codes, Moby Turbo(TM) may be used to optimize speed. MobyTurbo increases transfer speed without sacrificing ZMODEM flexibility or robustness. MobyTurbo is activated with the m option. The m option may be used with the sz or rz command. EXAMPLE: sz -m *.zip MobyTurbo may be used with ZMODEM AutoDownloads by adding the m option to the adlopts string. EXAMPLE: set adlopts m 13.1.4 Receiver Window Size Override ZMODEM-90(TM) allows the receiver to specify the window size, with the Wn option, overriding the sender's window size. SEE ALSO: Wn option 13.1.5 Almost 8 bit Environments The e and m options may be used in conjunction with the xmtxesc and zmrxesc string parameters may to specify one or more control characters which cannot be passed over the serial line. SEE ALSO: zmtxesc, zmrxesc string parameters for details 13.1.6 7 Bit Environments ZMODEM-90 automatically detects 7 bit environments and adjusts accordingly. If the environment is known to be 7 bits, use the E option to guarantee 7 bit compatibility in minimum time. EXAMPLE: sz -E file.doc When transferring files with a large number of bytes with the 8th bit set, the P ("pack") option may be used to optimize 7 bit encoding. EXAMPLE: sz -P zipfile.zip 13.1.7 Manual ABORT If a ZMODEM transfer fails abruptly under exceptional conditions the program on the remote machine may be manually terminated by repeatedly typing Ctrl-X characters at it until the program exits. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 55 13.2 XMODEM Family Protocols 13.2.1 TRUE YMODEM(TM) Developed in 1981, YMODEM is finding its way into many communications programs. With Omen Technology's Enhanced Data Recovery(TM), YMODEM gives excellent efficiency, integrity, and good robustness in many applications. True YMODEM transfers one or more files in a batch, without alteration or added garbage characters. True YMODEM also preserves the file date across multiple time zones. ZCOMM and the Unix(TM) rb and sb programs preserve the file modification date.[1] 13.2.2 YMODEM-1k The sb k option (1024 byte blocks) may be used to enhance throughput, especially when using timesharing systems, satellite links, or packet networks that can support the longer blocks. EXAMPLE: sb -k *.c *.h sends all .c and .h files in the current directory with 1024 byte blocks.[2] YMODEM and YMODEM-1k transfers can be received with the rb or F3 commands. YMODEM file transfers with Unix and VMS systems are discussed later in this chapter. Some programs claim to support YMODEM but actually use XMODEM with 1024 byte blocks. These programs do not meet the YMODEM Minimum Requirements defined by the YMODEM protocol. One can use ZCOMM's XMODEM sx -k and rc commands with these traditional programs. 13.2.3 YMODEM with OverThruster YMODEM and YMODEM-1k file downloading from networks and timesharing systems is slowed by response times. This slowing may be significant even when 1k blocks are used. With some systems, one can speed up YMODEM downloads by using the o option with the rb command to receive the file. Because OverThruster(TM) defeats error recovery, a line hit will usually abort a download. OverThruster(TM) may be used with X.PC or MNP error __________ 1. Controlled by the d and z numeric parameters 2. ZCOMM switches to 128 byte blocks at the end of a file when the length warrants. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 56 correcting link level protocols. EXAMPLE: rb -o SEE ALSO: O numeric parameter 13.2.4 XMODEM-1k The XMODEM-1k protocol transfers one file per command with 1024 byte blocks and a nominal 16 bit CRC. The file name must be entered for both the sender and the receiver. Programs lacking ZCOMM's Cybernetic Data Recovery(TM) logic are less likely to transfer data accurately under marginal conditions. XMODEM's use of every possible 8 bit code limit its effectiveness in many applications. The end of the file may be padded by up to 127 or 1023[3] garbage characters. To send a file with XMODEM-1k: sx -k file1 To receive a file with XMODEM-1k: rc file1 13.2.5 XMODEM-CRC (with fallback) The XMODEM-CRC protocol transfers one file per command. The XMODEM-CRC protocol requires the receiving program to initiate an XMODEM-CRC transfer. The file name must be entered for both the sender and the receiver. Even with CRC-16, programs lacking ZCOMM's Cybernetic Data Recovery(TM) are less likely to transfer data under marginal conditions. XMODEM-CRC's short data blocks and use of every possible 8 bit code limit its effectiveness in many applications. The end of the file may be padded by up to 127 garbage characters. To send a file with XMODEM (or XMODEM-CRC): sx file1 To receive a file with XMODEM-CRC: rc file1 13.2.6 Classic XMODEM The original MODEM protocol, developed by Ward Christensen, is supported by a large and growing number of programs operating on a variety of micros and minis. The base level XMODEM protocol gives good results when used over low error rate direct telephone connections. XMODEM's short data blocks and use of every possible 8 bit code preclude its application in many environments. __________ 3. Some programs (including ZCOMM) limit this padding to 127 bytes. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 57 File transfers with this protocol add up to 127 garbage characters to transferred files. The XMODEM protocol can transfer one file per command. The file name must be entered at both the sender and the receiver. To send a file with XMODEM: sx file1 To receive a file with Classic XMODEM: rx file1 13.2.7 Relaxed XMODEM ZCOMM's XMODEM and YMODEM support has been optimized for maximum reliability with a wide variety of systems under a wide variety of conditions. The default XMODEM and YMODEM timeout parameterss are "relaxed" timings. They rarely need to be lengthened except under the most sluggish of conditions. The zmodem t, T, and p numeric parameters (q.v.) control timeouts for XMODEM, YMODEM, and ZMODEM. The default values allow 10 seconds for a packet to appear and a 10 second pause within a packet before starting error recovery. EXAMPLE: zmodem pt200 pp150 :: Set more relaxed X/Y/ZMODEM timing For best reliability, Omen Technology does not recommend tightening these timings for XMODEM and YMODEM transfers on noisy lines. 13.2.8 XMODEM with OverThruster XMODEM file downloading from networks and timesharing systems is slowed by short blocks and long response times. With some systems, one can speed up downloads by using the ro command to receive the file. Because OverThruster(TM) defeats error recovery, a line hit will usually abort a download. With nearly error free connections, one can save enough time from the increased throughput to make up for the failed transfers. OverThruster(TM) may be used with X.PC or MNP error correcting link level protocols. EXAMPLE: ro file1 EXAMPLE: rb -o SEE ALSO: O numeric parameter 13.2.9 YMODEM-g: Traditional Overdrive The proliferation of error correcting modems has sparked a proliferation of YMODEM-g programs, more and more of which actually meet minimal YMODEM protocol specifications. YMODEM-g transmits 0 or more files per batch with an ACK-less variant of YMODEM-1k. The sender does not wait for individual data blocks to (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 58 be acknowledged, allowing high speed transfers with error correcting modems. YMODEM-g assumes an error free communications channel. A single transmission error or character lost because of DOS or TSR interrupt latency ruins the entire transfer, and YMODEM-g does not support Crash Recovery(TM). ZCOMM supports True YMODEM-g with the sb and rb -g commands. EXAMPLE: sb *.old Sends files in the current directory with YMODEM or YMODEM-g protocol. The receiver controls whether YMODEM or YMODEM-g is used for the transfer. EXAMPLE: rb -g Receives with YMODEM-g protocol. 13.2.10 XMODEM Mutants Misrepresented as YMODEM Despite continuing education efforts, a few lazy software providers insist on identifying their mutant XMODEM protocols as "ymodem". They choose to ignore the definition of YMODEM that Ward Christensen wrote when he coined the term YMODEM in his April 1985 message: (a) a record 0 containing filename date time and size (b) a 1K block size option (c) CRC-16. In case of questions, please refer to ymodem.doc, part of yzmodem.zoo (yzmodem.arc) for for the official YMODEM protocol. (Available in Omen's ZMODEM Developer's Collection.) 13.2.11 Qmodem-G/Streaming XMODEM The Qmodem program and certain bulletin boards provide an ACKless XMODEM mutant protocol selected with the Qmodem G protocol menu choice. The sx and rx -g commands support this mutant XMODEM. EXAMPLE: rx -g qmodem.fil 13.2.12 WXMODEM (People-Link) ZCOMM supports WXMODEM protocol downloads with the rw command. On the People-Link timesharing service, WXMODEM downloads are faster than XMODEM downloads. Throughput, reliability, accuracy, and amenities are not as good as ZMODEM or SuperKermit, but neither of these protocols are currently available on that system. WXMODEM adds up to 127 garbage bytes to transferred files. Omen Technology does not recommend WXMODEM for use over noisy phone lines. EXAMPLE: rw file1 (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 59 13.2.13 MODEM7 Batch The MODEM7 batch protocol passes CP/M file names from the sending program to the receiver one character at a time. The compatibility, throughput, and reliability problems of this kluge prompted the development of YMODEM. Nonetheless, when it becomes necessary to transfer files with a program lacking more advanced protocols, MODEM7 batch is better than nothing. File names transmitted with the MODEM7 batch protocol must obey the restrictions of both 8 bit CP/M and DOS. The f option cannot be used with MODEM7 batch. Data transfer within MODEM7 batch uses XMODEM protocol, and all of XMODEM's weaknesses discussed above apply to MODEM7 batch. MODEM7 batch does not preserve the modification date or exact file contents. EXAMPLE: s7 file1.ext *.baz sends files with MODEM7 batch. EXAMPLE: r7 receives one or more files with MODEM7 batch. 13.2.14 Telink/FIDO The Telink protocol expands upon the MODEM7 batch kluge with a specially formatted block containing the length of the file and the local DOS time and date. All of the MODEM7 batch compatibility and reliability problems apply to Telink.[4] The zmodem Z numeric parameter or the z file transfer option may be used to correct the time/date stamping of files transferred between different time zones. EXAMPLE: zmodem pZ120; st file1.ext *.baz Sends the specified files with a 2 hour time zone adjustment. EXAMPLE: rt -z60 Receives one or more files with a 60 minute time zone adjustment. 13.2.15 SEAlink When transferring files with the CLINK 1.13 compatible programs, ZCOMM's rb and sb commands recognize SEAlink's modified Telink protocol. The rb command allows a transmitting SEAlink program to use sliding windows. Telink time zone and file name considerations apply to SEAlink. In addition, because SEAlink uses all 256 of the possible 8 bit codes for both data transfer and protocol management, some modems and networks that operate with XMODEM __________ 4. ZCOMM's rt and st commands were verified with Minitel 3.0 by Tom Jenning's Fido Software; other Programs may not produce the same results. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers Version 17.78 TurboDial 2.35 Universal Line Printer Edition ZCOMM User Manual 60 will not accommodate SEAlink. As with the MODEM7 and Clink protocols mentioned above, the SEAlink protocol is included for convenience in situations where the YMODEM and ZMODEM protocols are not implemented.[5] EXAMPLE: zmodem pZ120; sb file1.ext *.baz Sends the specified files to a SEAlink program with a 2 hour time zone adjustment. EXAMPLE: rb -z60 Receives one or more files from a SEAlink program with a 60 minute time zone adjustment. __________ 5. ZCOMM's SEAlink was verified with CLINK 1.13 by Systems Enhancement Associates. Other Programs may not produce the same results because of ambiguities in the SEAlink documentation and undocumented protocol variants. (C) 1990 Omen Tech Inc Chapter 13 Protocol File Transfers