Subject: H89 as serial terminal

From: "Jason J. Gullickson" <[email-masked]>
Date: Thu Mar 27 15:08:56 2003

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

[email-masked]

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From: "Steven N. Hirsch" <[email-masked]>
Date: Thu Mar 27 17:13:33 2003

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

Yes.  The H89 was an H11 terminal with CPU and drive control boards added.  
I think you need to physically remove these and plug the cable from the
DB-25 connector into the terminal PCB.

I'm not too sharp on the details now, but I successfully converted several 
of them in this manner, circa 1990.

Steve

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From: [email-masked] (Tony Duell)
Date: Fri Mar 28 12:47:46 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

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From: "Patrick Rigney" <[email-masked]>
Date: Fri Mar 28 12:53:14 2003

> computer 'console port', serial port PCB) is the same.

Ouch...

> 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

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From: [email-masked] (Tony Duell)
Date: Mon Mar 31 19:12:25 2003

> terminal emulation program.  MDM712 comes with a serial port driver for

This is obviously some new definition of 'much easier' :-)...

You're suggesting I find some program I've never heard of (OK, google 
will presumably find it) and then transfer it onto an H89 disk -- some 
H89s have hard-sector controllers only, so transfering it could be 
'interesting'... What if the only OS you have for your H89 is HDOS? (I 
assume this is a CP/M program).

I'm suggesting opening the case (2 spring catches) and swapping round 2 
internal cables. No rewiring, no soldering, etc. Admittedly the terminal 
logic board is a _pain_ to get to, but.... 

I guess if you just want to use the H89 as a terminal, then the hardware 
solution is easier (you also don't have to boot CP/M and run a program). 
If you want ot be able to switch between using it as a computer and using 
it as a terminal then you need to track down this program.

> serial cards... I don't know which ends up being which or whether MDM712

I think the 3-port card (3 off 8250) is standard... Now there's a thought 
-- putting 16550s in an H89 and modifying the software to use the FIFOs...

> lets you choose, all of my '89's are down right now. :-/

What's wrong with them? These machines are not exactly complicated or 
hard to fix (at least not compared with some machines I've worked on).

-tony

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From: "Patrick Rigney" <[email-masked]>
Date: Mon Mar 31 19:57:20 2003

> hard to fix (at least not compared with some machines I've worked on).

Tony,

One, new to me, is popping caps and just needs a little TLC, I think; I
haven't yet left it on long enough to figure out how much of it is working.
It sounds like a popcorn popper, doesn't smell as nice.  It goes throught he
motions at power up, but can't read a diskette.  One was delivered to me
stripped of its serial card and floppy controller, and I've just this week
received replacement parts for it (both marked suspect but I'm undaunted).
That batch also included a H/Z-37 soft-sectored disk controller, and an
H/Z-67 hard disk controller (apparently SASI) that I'm eager to play with.
My "reference" machine is currently in storage after a rather aggressive
remodel of part of my house (which includes the creation of a new work area
for all of these machines plus some).  You're correct, they're not hard to
work on; having little time and fat fingers not well-suited to tight spaces
have been my biggest barriers.  I've got another project going right now,
and until that's launched, I won't have time, so this state of affairs is
likely to persist for the '89's and other recent acquisitions for the
foreseeable future.

> This is obviously some new definition of 'much easier' :-)...

Yeah, OK. :-) Dwight already took me to the woodshed for that.  Poor choice
of words on my part.

Patrick

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From: [email-masked] (Tony Duell)
Date: Mon Mar 31 20:01:28 2003

> One, new to me, is popping caps and just needs a little TLC, I think; I

If you're lucky that will just be old capacitors that have decided to 
fail. If you're unlucky, it'll be a PSU problem (bad ground on one of the 
3 terminal regulators?) that means that one of the supply lines is way 
overvoltage. Which will then kill the capacitors _and chips_.

[...]

> have been my biggest barriers.  I've got another project going right now,

The rule I discovered when working on my Z90 was 'Think what order the 
various bits were made/installed, and take the latest ones out first'. In 
other words, take ou the disk drive, then the expansion PCBs, then the 
CPU board, and finally the terminal logic board (OK, and then the monitor 
parts if you have to). 

-tony