[linsomniac]

I had a very similar experience. For 1995 it was really quite amazing! Loved how quickly it connected ("I never have to listen to a pair of modems sniff each others butts again!"), and that I could place/receive a call while still being online. Also, the voice quality really was superior, even when receiving a call from a regular POTS call on the other end.

Unfortunately, after the first year of having it, US West (Omaha Nebraska USA telco) started "actively discouraging" ISDN (source, I worked at US West at the time and was asking a sales tech about it). I had wanted to move to a larger apartment in the same building, but doing so would have increased my ISDN cost from $40/mo to by-the-minute $400-ish/mo.

I used a Motorola Bitsurfer on Linux. But my other computer, an HP 9000s712 ("Gecko") had an ISDN modem that was SCSI. That seemed like a weird choice, but their serial port was only rated up to 115.2K so it was the only choice for 128K.