Tandy Professional Forum   Section: Model 4 / 4P
Subject: PC to Tandy Printer   Total messages: 4
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#62747   1 Reply   12/19/96   11:29:06
From: Gil Parrish, 73430,1546
To:   All

I'm still investigating the question of attaching a standard
MS-DOS type PC computer to a Tandy printer intended for the Model
III, 4, or whatever.  My understanding is that Tandy's version of
the parallel interface on the printer is not the same as the PC
world's version of the parallel interface (thanks to IBM), and as
a result a special cable is needed to attach a PC to a Tandy
printer.  I know Tandy used to market the needed cable, and may
still market the needed cable for all I know.

Is there someone out there with one of those cables and a
multimeter who can tell me what pin on the PC side attaches to
what pin on the Tandy side?  I'm *most* interested in where  13
and 14 on the PC side attach to on the Tandy side, and where 13
and 31 on the Tandy side attach to on the PC side, but confirming
all the connections would be useful.  Alternately, if someone has
one of these cables for sale reasonably, I'd be interested.

Logic tells me there must also be a special cable to attach a
Tandy computer to a regular parallel printer instead of a Tandy
parallel printer, although this cable would APPEAR from the
outside to be identical to a standard Tandy printer cable (edge
connector on one side, Centronics on the other).  Anybody with
info on these?


#62760   Reply to #62747   2 Replies   12/26/96   19:03:02
From: Don  L. Morrow, 104362,63
To:   Gil Parrish, 73430,1546

Gil,

I made my DWP 230 Tandy printer work on my PC using a standard
printer cable and swapping pins 31 & 33 at the 36 pin printer
connector , pin 13 is NBusy and 14 is ground.

This may help you.

Don


#62763   Reply to #62760   12/27/96   10:13:29
From: Gil Parrish, 73430,1546
To:   Don  L. Morrow, 104362,63


>>I made my DWP 230 Tandy printer work on my PC using a standard

>>printer cable and swapping pins 31 & 33 at the 36 pin printer

>>connector , pin 13 is NBusy and 14 is ground.

I'll see how this correlates with the other information I've
received.
Thanks for the help.


#62764   Reply to #62760   12/27/96   11:14:24
From: Gil Parrish, 73430,1546
To:   Don  L. Morrow, 104362,63


>>I made my DWP 230 Tandy printer work on my PC using a standard

>>printer cable and swapping pins 31 & 33 at the 36 pin printer

>>connector , pin 13 is NBusy and 14 is ground.

OK, I've looked back at my notes on this.

As you said, the differences in the two standards are on 13, 14,
31 and 33. By shifting wire 31 from the computer end to pin 33 on
the printer end, /Init would be correct for both.  Wire 33 (which
is ground) could be shifted to pin 14 on the printer end, also
ground.

I'm unclear about wire 13 from the computer.  The computer
expects "Slct Out" but I see no corresponding pin on the Tandy
printer end.  On wire 14, the computer expects "/Auto Feed XT"
but there is no corresponding Tandy pin.  As to the printer, it
expects "/Busy" on pin 13; I see a "Busy" but no "/Busy" on the
PC side.  Where would I connect all these wires/pins?  Pin 31 on
the Tandy side makes no connection anyway; would I leave Pin 31
alone, or tie it to ground or something?

How did you come to make your own cable?  Did you try a regular
cable and just not have any luck with it?  People have made
noises to me that it is DANGEROUS to connect the wrong cable, and
that it might damage the power supply on the computer, printer or
both, but I don't see how that would occur.

Thanks for your help.


