ISDN was a great upgrade for me in the 1990s, and once I found out how to couple two lines into one "massive" 128k, it was pretty mind blowing. Connecting to the Internet was also snappy (as opposed to dialup with the whole modem song) and could even be done on demand if you were brave.
Well, it wasn't actually 128k. Technical reasons limited it to 112k. That's why 56k instead of 64k modems. There was the Shotgun Modem which required 2 separate phone lines, but would bind them together. I never bothered reading up on how binding 2 PPP connections worked, but I guess it worked well enough that it was a legit product being sold. I went from 28.8k to ISDN, so I skipped the 56k altogether.
Of course, ISDN and 2 56K connections are only similar in bitrate and are not the same thing at all.
> Well, it wasn't actually 128k. Technical reasons limited it to 112k. That's why 56k instead of 64k modems.
That’s not fundamentally true about ISDN - in North America, at least, most basic rate connections and every single PRI I ever encountered had eight-bit-clean channels and were true 64kbps.
With modems (I assume you mean analog modems,) that was only part of the reason. There were others that would have been far more difficult to solve in practice, and there was largely no point in doiny so as xDSL technologies came around at roughly the same time.
Multilink PPP worked quite well, even beyond bonding two channels.
You're right the BRI was actually 144k, 2x64k B channels and 1x16k D channel. 112k was available on misconfigured hardware and gimped bit-robbing lines where some of the bits on the B channels were used for signaling in lieu of a D channel.
Yeah I think the binding of the lines was much easier with ISDN as one never went through the analog level (except if you want to be really pedantic). It was digital from the ISDN adapter. No ringtone etc.
