[Coco] CNR Engineering SP-3 (serial to parallel interface) - Manual?

Arthur Flexser flexser at fiu.edu
Mon Dec 24 00:57:28 EST 2018

On Sun, Dec 23, 2018 at 6:04 PM Andrew <keeper63 at cox.net> wrote:

> Art, if I'm understanding you right, I just need to use regular serial
> port output commands (either POKEs or PRINT #-2), at the proper baud
> rate the device is set up for (it has a switch), and I just need the
> centronics pinout to know which pin is what for the data output?

Yep, that's exactly right.  If you are using the interface with something
other than a printer, you may need to knock out the part of the ROM printer
output routine (at $A2BF) that checks whether the printer is ready to
receive the next character.  Involves changing a conditional branch to an
unconditional one in two places.


> My thought is to use the output for general device control, maybe
> controlling relays (either a pre-built relay module or via a transistor
> of course), or maybe steppers, etc - I might get a hair up my butt and
> try to send PCL to one of my HP LaserJet printers.
> The device has a couple of rotary switches on it; one to select baud
> rate (300 - 19200), and another to bypass it (turn it off), or select 7
> or 8 bit (output I guess?). It has three cables and a power supply
> hard-wired (it appears) to it. One cable is the centronics interface,
> then other two are 4-pin DIN connectors (one male and one female).

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