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The phone company operates trunking lines, which multiplexes some large number of phone lines over a single physical medium. T1 for example is a common standard
by hydrogen18 12y ago
The phone company operates trunking lines, which multiplexes some large number of phone lines over a single physical medium. T1 for example is a common standard to deliver 24 voice lines over a single physical medium. Historically, you'd have equipment at both ends. One at at central office and one near a group of subscribers, like a street full of homes.
Basically the dial up server just had hardware that directly terminated the trunking line into it. The modem part might be done in software, might be done in hardware, or a little bit of both. By doing this it is practical to have a single machine serving 100s or even 1000s of customers.
- BorisMelnik 12y agowow thank you - that makes sense because I never remebr seeing huge banks of servers. there were definitely a few but I never remember seeing any kind of "rows of modems" or anything. So you are saying (more or less) 1 T1 for every 24 lines or 24 customers?
- icedchai 12y agoEach T1 gave you 24 lines. Generally, early ISPs were heavily over-subscribed, meaning there were many more customers than available phone lines. You might call in and get a busy signal!
- hydrogen18 12y agoI remember getting up early on Saturday mornings so I could get connected the to the local FreeNet before all the lines were busied.
- BorisMelnik 12y agoyes! I remember hanging up and reconnecting like 5x if I 'didn't get a good line' :)
- kjs3 12y ago24 lines. As ISPs got bigger/more efficient, they moved to T-3/DS3 lines (672 lines per). I can only think of a handful of ISPs that went bigger than that. By the time OC-3 and larger channels became cost effective, the era of dial-up was pretty much over.
- deleted 12y ago[deleted]