TRS80 Model 3 i/o connectors

From: Glen Goodwin <acme_ent_at_bellsouth.net>
Date: Thu Oct 31 09:42:00 2002

> From: Tony Duell <ard_at_p850ug1.demon.co.uk>

> Most of the I/O connectors are on the bottom...

Okay, *bottom of the unit towards the rear* :>)
 
> So far, so good. I assume you've identified the mains input as well.

Yeah, that would be pretty hard to miss!
 
> On the bottom are 4 connectors. The 2 neares the back of the machine are
> on the CPU board and consist of the parallel printer port (34 pin,
> towards the floppy drive side of the machine) and the I/O expansion bus
> (50 pin).
>
> In front of the parallel port is another 34 pin edge connector, which is
> part of the floppy controller card. It's for external floppy drives (You
> can connect 2 more drives here, I think you set them as DS0 and DS1, and
> you need to terminate the last drive on the cable).
>
> In front of the I/O bus is the DB25 RS232 port.
>
> > parallel port as a 34-pin card-edge connector (which I suppose needs a
> > Tandy-specific cable to attach to a printer), but the problem is that
there
>
> Yes, but it's an easy cable to make up. It's just a 34 pin edge connector

> on one end of a piece of ribbon cable and a 36 pin Blue Ribbon
> ('Centronics') plug on the other. Leave pins 18 and 36 on the BLue Ribbon

> connector unconnected, match up the pin 1s of the 2 connectors. Then just

> crimp the connectors onto the cable -- there are no twists or swaps to
> worry about.

Thanks for the information. I'll be poking around this critter more this
weekend. Any gotchas I should know about?

Later --

Glen
0/0
Received on Thu Oct 31 2002 - 09:42:00 GMT