I think the unique thing about this IBM sound cards is that it had a programmable DSP which made it much more flexible.
- It had a four-voice synthesizer, so it could play music / synthesize voices, etc over the line.
- It had a handset input, I think w/digitizer, so it could be used as a voice distorter.
- It supported Bell 202 1200 bps half-duplex to another Cat II.
- It could control a tape recorder, so it could be used as an answering machine.
- It could control home appliances via BSR X-10.
- It had RS-232 support, so it could be used as a serial printer controller.
It was not a conventional modem.
I think the unique thing about this IBM sound cards is that it had a programmable DSP which made it much more flexible.