TRS-80 Printer "Interface" Cables

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sat Oct 30 18:27:40 2004

>
> Hello all,
>
> Can anyone tell me the difference between the two different TRS-80
> Model 1 Printer Interface Cables? These are the cables used to connect

I remember those... I used one for a year on my Model 1 with a CGP115
printer. The next year I got the EI and a disk drive...

> a Line Printer directly to the expansion bus on a Model 1 without using
> the Expansion Interface. They are ribbon cables with a "little black
> box" midstream containing the printer port circuitry. The 26-1411 was
> originally for the LP1 and the 26-1416 was for the LP2.
>
> Now, I know that these also worked on subsequent Line Printers, and my
> understanding was that the 26-1411 worked on most while the 1416 only
> worked on a few (!)
>
> What exactly is the difference? Does anyone know? I'm coming into
> possesion of a LP3, but I only have a 26-1416 cable.... I don't know if
> this will work (I'm very confused!)

Firstly a minor quirk. The interface circuit gets its 5V power from the
printer (pin <mumble> of the Centronics connector. Radio Shack printers
provide this, some others may not.

Now, IIRC the cable is in 2 parts. A short part which plugs into the M1
expansion connector, and which includes the interface chips, and a longer
part that fits onto a card edge on the interface PCB and connects to the
printer. It's the second part that's different between the 2 cables I
think. One of them has a normal 36 pin Blue Ribbon connector, the other
has an edge connector. You have to use whichever one fits your printer.

-tony
Received on Sat Oct 30 2004 - 18:27:40 BST