16 Jul
1998
16 Jul
'98
9:28 p.m.
A _very_ good
book for the older stuff (manual switchboards, relays,
step-by-step 2-motion selectors) is called 'Telephony' by (IIRC) Herbert
and Proctor. It's a UK book,...
> 'Tip' and 'Ring' refer, of course to the 2 contacts on a 3-wire jack
> (phone?) plug - like a stereo headphone plug, used on the old manual
> switchboards. The other contact - sleeve (aka the 'P wire') was used in
> the exchange to check if a line was in use (P=Private, I think).
I always did wonder. I've got a couple of old (can't remember the exact
date, but I'd say early 70's at a guess) answering machines somewhere
which make use of such plugs. I'd love to wire one of these things up to
a phone circuit if possible, I doubt that it could be done though - the
systems were badged "Ansafone" IIRC, making use of enormous reel-to-reel
tape decks and foot pedals... :)
(I suppose this could be judged almost-on-topic, if the phone system is
deemed to be some giant computer, and the technology, after all, is more
than 10 years old)
cheers
Jules