I love a good telephone story. In true nerd fashion, I just want to object to one tiny detail, which is technically correct but misleading:

>In the worst case, even a humble single-party line could sap the capacity of the exchange's switching equipment if it stuck off hook.

This is true, to an extent - if the exchange did nothing about it, an off-hook phone could consume an expensive piece of hardware (a sender) that would otherwise only be in use during the time that a customer was dialing. However, because this was something that people could do _on purpose_ (and frequently did, to avoid incoming calls) as well as be caused by a relatively common fault (short circuit between the two phone wires), the phone company took steps to make this less expensive. In later switches, each line would have a dedicated relay to handle this.

If you want to learn more about this minutia, or about old telephone systems in general, the Connections Museum YouTube channel is an excellent resource:

https://www.youtube.com/watch?v=ZaKGgDaApkM

Remarkable level of detail. Favorited so I can read sometime when I'm not at work, while I also ruminate on how many other submissions I've favorited for the same reason and never returned to.

God I love this blog. Thanks for submitting it!