Can't seem to use my SC126 with a VersaTerm

[Mx Argent]

Has anyone gotten a VersaTerm talking to a RomWBW machine? I'm in a bit of a weird position here where I can use my SC126 fine with a FTDI adapter to a PC running a terminal emulator, and I can get the VersaTerm talking fine to my PC using the same adapter, but I can't seem to get the SC126 and the VersaTerm to engage in conversation with one another via their respective TTL serial ports. I'm crossing RTS/CTS and TxD/RxD appropriately, I'm configured for 115.2k/8/n/1 with no flow control, yet i'm not getting anything from the computer.

It's the same story with a 232 level shifter hooked up to Port A on the SC126 and the 232 serial port on the VersaTerm - I see LED blinks on the 232 step-up module that indicate the board trying to engage in communications, but no actual activity shows up on my terminal.

[Wayne Warthen]

It looks like the RS232 DE-9 on the VersaTerm is DTE.  If your level shifter on Port A of the SC126 is also DTE (as would be normal), then you will need a null modem cable or adapter.

The pinout of the TTL port on the SC126 seems to be entirely different than the pinout on the VersaTerm.  I'm not sure how you wired it exactly, but you would need to do more than simply cross pins 4/5 and 2/6 of the SC126.

Thanks, Wayne

[Mx Argent]

Oh yeah, I'm using a null modem cable while working with 232. For that arrangement, it's straight through (5v-5v, Gnd-Gnd, Tx-Tx, Rx-Rx, RTS-RTS, CTS-CTS) from Port A to the TTL-232 adapter (powered via Serial A with P4 bridged), then I'm letting the null modem cable do the crossing over. Right now I'm just making the connections individually using f-f jumper wires, the plan's to make something more permanent later once I've figured out acceptable wiring.

I'm starting to wonder if simplifying my approach and going for the RP2040 VGA term board might be the better option. I'm mostly just trying to get the machine running standalone ahead of planned exhibition at VCF Midwest. (I was mostly hoping to use the VersaTerm to keep things consistent between the SC126 and a Duodyne stack that'll be part of the same exhibit. There's going to be a third machine involved here, but I want that to have graphics hardware.)

[Wayne Warthen]

Gotcha.  It is very surprising that the VersaTerm is not working.  I don't have a VersaTerm, but it is implementing a very straightforward serial interface.  I really don't know what else to try.

-Wayne