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Old 30th Nov 2017, 11:05 pm   #32
philthespark
Pentode
 
Join Date: Oct 2017
Location: Newton-le-Willows, Merseyside, UK.
Posts: 158
Default Re: Interconnecting old telephones?

Apologies for dragging up an old thread here, I worked at BT for a spell on overhead lines, I remember many years ago trying to get a couple of old phones ringing, and I struggled too, However, I had a friend and his father worked in an exchange, he loved his job and would chat about it for hours, anyway basically the gist of it was this.
A telephone ran typically at 48Vdc, however, the ring signal was around 90v, and was a modified form of AC, I can't remember the term he used, this was proved to me one day at home. I was altering the wiring on our line, it was before the plug and socket system, I was just connecting a pair and I got a fairly hefty shock, the phone I was connecting then began to ring, oh yes I never forgot that one.
In a way it reminded me of a recent argument with a bloke who said that there was no need to connect terminal 3 (ring terminal) when installing phone extensions these days. In fact, he insisted, it could actually affect the broadband, one problem with this is for anyone wishing to use older equipment, a lot of older answering machines actually needed the third wire, otherwise they didn't "know" when a call was coming in. When I pointed this out to him his attitude was "well who uses the old gear anyway"
Some people have no appreciation of the older stuff, at least with the older wired phones you could still make a call in a power cut. Thankfully there are still a few of us who appreciate the older technology.
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