27 Mar
2003
27 Mar
'03
6:19 p.m.
The hardware solution is to disconnect the internal
serial cable from the
termianl logic PCB (the rearmost vertical PCB in the machine) and replace
it with one of the cables that goes to a DB25 connector on the back
(these cables are normally connected to the serial port PCB plugged into
the computer mainboard, just in front of the terminal logic PCB). The
cables have a Molex 0.1" pitch SIL connector on the end, and fortunately,
the pinout of all the internal serial connectors (terminal logic PCB,
computer 'console port', serial port PCB) is the same.
Ouch...
The software solution is to write a little program
that transfers
characters between the computer's console port and one of the other
serial ports. This will then make the computer section appear as a
transparent link between the terminal and the outside world.
much easier than any of the above... get a copy of MDM712 or similar
terminal emulation program. MDM712 comes with a serial port driver for
H8/89. Plug your device into the spare serial port on the back of the
(unopened) machine, and that should do it. Some '89's have three-port
serial cards... I don't know which ends up being which or whether MDM712
lets you choose, all of my '89's are down right now. :-/
Patrick