WiModem232 with color computer - Printable Version

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WiModem232 with color computer - voidstar - 07-08-2022

Has anyone gotten a WiModem232 to work with a Tandy Color Computer 1, 2, or 3?  The mid-1980s ones, not the older TRS-80's.

The CoCo 1/2/3 have a Serial I/O port at the back.   I'm not sure if anyone ever actually made a modem out of that - since I've read it's rather inefficient, and Tandy did sell a RS232 Pak (I think with a DB25 connector that was intended to connect over to a modem).  I'm not sure if the RS232 had a UART, but in any case apparently it supported much higher speeds than the "Serial I/O" port at the back.

Still, I don't mind even being limited to 2400 baud - I'd like to just use the Serial IO port.  I know PETTERM exist for the Commodore PET user-port (limited to 2400 baud), seems similar software should be possible for the Color Computer.

Maybe it's just a matter of finding/building the right 4-pin DIN to DB25 adapter cable?

There is a chart on page 12 of this document that describes the Color Computer 4-pin RS-232 output (and the document then also describes that RS-232 Pak):
Color Computer RS232 Communications (sparksandflames.com)

RE: WiModem232 with color computer - voidstar - 07-11-2022

I got it working! On the 4-pin DIN to Serial cable (or "DriveWire" cable), you have to swap the TX/RX pins.

RE: WiModem232 with color computer - voidstar - 07-11-2022

Here is a shot of what that looks like (I just use jumper wires between the serial cable and WiModem232).

I may splice the "driveWire" cable itself and just swap the wires inside of it.   Or does anyone make a "invert-tx/rx-pins" kind of adapter already, in either the DB9 or DB25 side?  Could be a simple inline thing.

EDIT: I could only run it at 1200 baud though, on a stock CoCo3.  I haven't done a firmware update on the WiModem232 though, and it says one is due.  Still, it is fairly well known that the Tandy CoCo SerialIO wasn't the most efficient (Tandy even sold a separate RS232 Pak that was more efficient at interfacing with a modem).


RE: WiModem232 with color computer - admin - 07-12-2022

Sounds like you are using NULL modem cable, and not a traditional modem cable. Those cables would have ALL of the various lines swapped.

I don't know what the max baud rate is for your particular machine. If you had that RS232 pak, it should work with the WiModem232 just like a real modem would.