I hve used an AEA PK-232 to do this. The 33 is connected to the PK-232’s console port, which is configured for 110 ASCII. (The 232 has an ‘autodetect’ feature which will set itself up for the correct terminal device)
The the 232 is commanded into Baudot mode (By typing ‘BA’ on the 33) and incoming AFSK will appear on the console device. It’s quite wierd to have the ASR33 clacking away at 45 baud – less than half it’s “normal” speed – but it works well
and I have used it at several demos I’ve run with Baudot and ASCII machinery running in parallel at the same time. I’ve also decoded Morse this way.
I know that there were several other similar devices available which also used an RS-232 / ASCII console and decoded various signal on their audio inputs. The PK-232 is the one I’m familiar with and seems to work well. And the are not
hard to find – I’ve had several of them over the years. Documentation is also archived in various places. Look for HAL, Heathkit, Kantronics, etc.
Finally one could use a USB – to Serial converter and run MTTY, FLDIGI, or similar, and send the output to the ‘serial’ port ad thus to the ASR33
Cheers
John KB6SCO
Carson City