H89 as serial terminal

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Mar 27 15:36:01 2003

> Is there any (easy) way to use an H89 as a serial terminal, VT100 even?

Yes, there are 2 ways to do it -- hardware and software

The H89 is acutally a computer and a serial terminal in the same box,
communicating via a very short RS232 cable. The terminal, which is
actually an H19, has an ANSI mode which is close to being a VT100 IIRC.

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.

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.

-tony
Received on Thu Mar 27 2003 - 15:36:01 GMT