[Rotundo]

I remember. It was very expensive for not a lot of extra bandwidth. You also needed a special ISDN phone or a, again expensive, box to convert the signal to normal POTS.

Not long after the cable company started offering 'broadband' at 115 kbps, quickly upgraded to 512kbps.

ISDN was a complete non-starter in my locale.

[LargoLasskhyfv]

In my locale it was much cheaper, because of massive push via subsidies from former gov-telco. We also had 2 x 64kb/s channels, for 128kb/s bundled(dynamically/on demand), plus signalling channel. Since it was so widespread you actually had a chance to enjoy very good voice quality, which often is still unsurpassed, today. Especially regarding latency. Again because of the wide availability, the not so special phones weren't that expensive, and adapter boxes neither. But nobody wanted these anyway, because old phones didn't give the good voice quality.