Comment by dspillett

6 hours ago

* 56k baud modems but even my USR (the best of the bunch) never got more than half way to 56k throughput*

56k modem standards were asymmetric, the upload rate being half that of the download. In my experience (UK based, calling UK ISPs) 42kbps was usually what I saw, though 46 or even 48k was stable¹ for a while sometimes.

But 42k down was 21k up, so if I was planning to upload anything much I'd set my modem to pretend it as a 36k6 unit: that was more stable and up to that speed things were symmetric (so I got 36k6 up as well as down, better than 24k/23k/21k). I could reliably get a 36k6 link, and it would generally stay up as long as I needed it to.

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[1] sometimes a 48k link would last many minutes then die randomly, forcing my modem to hold back to 42k resulted in much more stable connections

Even then, it required specialized hardware on the ISP side to connect above 33.6kbps at all, and almost never reliably so. I remember telling most of my friends just to get/stick with the 33.6k options. Especially considering the overhead a lot of those higher modems took, most of which were "winmodems" that used a fair amount of CPU overhead insstead of an actual COM/Serial port. It was kind of wild.

  • Yep. Though I found 42k reliable and a useful boost over 36k6 (14%) if I was planning on downloading something big¹. If you had a 56k capable modem and had a less than ideal line, it was important to force it to 36k6 because failure to connect using the enhanced protocol would usually result in fallback all the way to 28k8 (assuming, of course, that your line wasn't too noisy for even 36k6 to be stable).

    I always avoided WinModems, in part because I used Linux a lot, and recommended friends/family do the same. “but it was cheaper!” was a regular refrain when one didn't work well, and I pulled out the good ol' “I told you so”.

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    [1] Big by the standards of the day, not today!