Date   : Wed, 03 Apr 1985 10:26:00 EST
From   : dbrothers@DDN1.ARPA
Subject: APPLE ][ to KAYPRO on a null modem

I have transferred files from an APPLE ][ to a KAYPRO using MEX
on the KAYPRO and ZPRO on the APPLE ][ over a null modem at
speeds of up to 9600 baud. It worked beautifully.
I initially did it using modems at 300 baud and a phone, but found that the
phone line is unnecessary if you have a seriel card in 
the APPLE ][, you can easily use a null modem cable.
A null modem cable can easily be built. It is simply a
pair of db-25 connectors (Males usually) that have the following
pin connections: Pin 1 to pin 1, pin 2 to pin 3 at the other end,
pin 3 to pin 2 at the other end, pin 7 to pin 7, pin 6 to
pin 20 at the other end and pin 20 to pin 6 at the other end. The idea
is to swap the send
and receive lines and the dtr and cts lines.
If you have an APPLE ][ super serial card, then you don't need
to build anything. You can set the configuration block to the
TERMINAL mode and use your existing db-25 cable. Read the book
and you'll see that this configuration is the
same as having a null modem cable.

It should be possible to write the RWTS (read-write-track-sector)
code that resides at BD00-BFFF in an APPLE ][ in 8080 code
and make it run in a KAYPRO. The hard part would be to
get the documentation which describes how you access the
disk directly from 8080 code in the KAYPRO. You
would need to know how to turn on the motor, how to
check for write protect, how long to wait after turning
on the motor before reading, what the data really looks
like when you do a read (bit-by-bit read) and how
you define which disk drive you want to access. I
do not know if this information is available for the KAYPRO.
It is also possible to use MEX, MODEM7, or any other
xmodem-capable program to do quick APPLE ][ to KAYPRO
transfers. I like using MEX because it has wild card
capability. 

If the files you need to transfer
are ascii, rather than binary, it is
possible to use PIP on both ends
to transfer them from the APPLE ][ to the KAYPRO.
this is not the rpeferred method, however. There
is no checksum or CRC if you use PIP.
Best of luck...
Doug