I had a friend with a 56K ISDN line (data over voice channel) and it was much better performance (10's of milliseconds.)
I had a friend with a 56K ISDN line (data over voice channel) and it was much better performance (10's of milliseconds.)
Worthwhile to also mention that ISDN was full duplex, instead of half-duplex like dialup. The modems on either end would need to time-slice to allow bi-directional communication, which in a TCP laden world like the web meant that every interaction was orders of magnitude more latent than on ISDN, in which you had symmetrical, full-duplex 56k of bandwidth between you and the ISDN modem. That's the biggest reason why you had a significant decrease in latency.
Fortunately, I got cable internet around 1997 and never looked back.
My "favorite" thing when working tech support was explaining to people in expensive new subdivisions that Southwest Bell saved money by deploying pair gains instead of running more copper, and that's why they were never, ever going to see more than 33.6 (if very lucky) or 28.8 (more likely).
A common trick was to get them to add 3 commas to their dial string. That would prevent their modem from starting to train up until 3 seconds after they finished dialing. That would give our modems time to answer and start the 56K initiation. The delay would cause them to miss that, and then start trying to train up a much more stable 33.6 connection. It capped their max speed but made their connection a lot more reliable.
Later on, there were modems that required a CPU with MMX instructions. Dealt with that a lot when I ran my short-lived computer shop.
I made it a policy in '97 to only buy external modems.