MXO-KP26.ASM Notes


     This  overlay requires setting one of the option switches in 
your modem.  This must be done to respond properly to the ability 
of MEX to return to CPM,  then back to MEX, without disconnecting 
from the remote computer.   While this may not have been properly 
implemented in previous MDM7 overlays, it is the intent of MEX to 
set this discipline.

     If you are using a Hayes Smartmodem,  set switch 6, DCD, up.  
For a US Robotics password, set the 8HI switch to OFF.  For other 
Hayes  compatibles,  enable  the DCD line,  pin 8 on  the  RS-232 
connector as your modem documentation indicates.

     Note  that  code is included in this overlay for the  Kaypro 
internal modem.  This modem is interrupt driven via an additional 
PIO  port for modem enabling and dialing and is also  driven  via 
the  RS-232  port.   If the SET INTERNAL command is given with  a 
Kaypro without the internal modem, the computer will hang with no 
keyboard  recognition.   The  only recourse is to hit  the  reset 
switch.   The reason for this is the ports used for the  internal 
modem  do  not correspond in the non-internal modem  machines  as 
decoded  by  the  hardware.    The  internal  modem  serial  port 
corresponds  to the keyboard baud rate set port in the  non-modem 
machines (!).   Thus,  when the port is initialized, the keyboard 
receiver baud rate no longer matches the keyboard transmitter.

     The above caveat is, in my opinion, a small price to pay for 
an "all Kaypro product" overlay.  While it has not been tested on 
the Robie, it should work since the main board design is similar.

     The  reason  for discussing the above is to  caution  future 
modifiers of the overlay to be sure to test their overlays on all 
Kaypro  configurations,   otherwise  unexpected  results  may  be 
obtained.  I am not trying to be obnoxious about this - just want 
to  be  sure end users get working product.   Most of  us  expect 
later revisions to be "better" and someone who revises a file has 
a  responsibility  to ensure compatibility is maintained  if  the 
same file name is used.

John C. Smith
Manlius, NY
June 10, 1984