The Bell Ringer history on KITZ has a fascinating story about wire No 3 and its roll in the old scheme. Clive
[I use a BT REN booster box to take it up to 10 I think so it powers a home PABX, a burglar alarm ring out and two Sky boxes]. --- In [email protected], Terry Streeter <[EMAIL PROTECTED]> wrote: > > [EMAIL PROTECTED] wrote: > > I haven't connected more than two handsets so I am not exceeding the > > magic 4 REMs (whatever they may be). > > It's actually REN not REM. Stands for Ringer Equivalence Number - and > is used to calculate the loading on the line. When there is an incoming > call, the exchange sends an AC signal (can't remember what voltage, but > may well be in the region of 30V to 50V) down the wire. In the good old > days this activated an electromagnet which caused the bell in your > telephone to ring. Too many phones connected caused too much loading to > the line and there wasn't enough signal left to make the phone ring > reliably. One old phone had a REN of one, and the GPO set a maximum > limit of four phones allowed to be connected to any one line. > > This is all dredged from the dusty shelf at the back of my memory, and > may well be in error in places. > > Terry Streeter > NB Arun - Brierley Hill >
