Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!att!cuuxb!rbc
From: rbc@cuuxb.ATT.COM (~XT6511100~Rick Clark~C24~G15~6011~)
Newsgroups: comp.sys.tandy
Subject: Re: Tandy Printer + PC Compatible Query
Message-ID: <2718@cuuxb.ATT.COM>
Date: 12 Apr 89 16:05:26 GMT
References: <1370@cunixc.cc.columbia.edu>
Reply-To: rbc@cuuxb.UUCP (Richard B. Clark)
Organization: AT&T, Data Systems Group, Lisle, IL
Lines: 44

In article <1370@cunixc.cc.columbia.edu> walsh@cunixa.cc.columbia.edu (Edward E Walsh) writes:
>My classical Chinese professor recently replaced his Tandy PC (it sort
>of blew up or something; he wasn't very clear--blamed it on the maid)
>with a PC compatible (don't remember the make, a 47th Street Photo
>special that weekend).  He'd like to keep using his fancy Tandy
>daisywheel printer with the compatible.  He got a standard parallel
>cable and plugged it in, but then the printer goes dead--you don't get
>that nice "click-click" sound when you turn it on, the online light
>won't light, etc.  The printer self-tests ok as long as the cable's
>not plugged into it.  An Epson printer hooked up to the same computer
>with the same cable works fine.  The dip switches on the printer were
>all set as they should be for an IBM.  The printer still works fine
>with a Tandy cable and computer.  Any suggestions?  Will it only work
>with a true IBM or what?  Tandy said it should work, they don't know
>what's wrong, try another cable, etc., etc.
>
>Also, know if there's a printwheel he could get that has special
>characters for Swedish?
>
>Please reply to me via e-mail--I try to avoid addictive bboards...:)

For some reason this sparked a flame war by third parties about Tandy
incompatibility, and no one got around to answering the poor guys
question, unless they did so by e-mail as requested.

I was hoping to see the answer posted as I had the same problem trying
to connect my Tandy DMP130 printer to an AT&T PC 7300.  Power on does
not go through the initialization cycle, and the printer is unusable.
I eventually figured it out from the pin outs in the tech manuals.

The PC puts out its INIT lead on pin 31, while the printer is expecting
it on pin 33.  The PC puts out GND on pin 33.  The INIT input is active
low strobe, so the GND is holding the printer hostage.

The proper thing to do would be to invert pins 31 and 33 at one end.
What I did was just disconnect pin 33 in the cable.  I didn't really
care if my PC could send an init signal to the printer.  I don't think
the driver knows how to anyway.

My PC is not an IBM compatible, so it is not guaranteed to be the same
situation as an IBM PC, but disconnecting pin 33 is a safe enough experiment.
-- 
=Richard B. Clark
 Lisle, IL       ...!{att,lll-crg}!cuuxb!rbc  OR cuuxb!rbc@arpa.att.com