[sci.electronics] Voltage on phone line?

earlj@ribs.UUCP (Jim Lips Earl) (01/10/90)

I installed a new telephone at my parent's house last weekend, and while
checking the wires, noticed that the DC voltage across the phone line
(with the phone on-hook) starts at around 40-50v, then slowly drops to
around 15-20 volts, then suddenly zips back up to the 40-50v again, repeating
this cycle every 5-7 seconds.  I thought there was something wrong with one
of their phones, causing the line to do wierd things, so I disconnected all
the phones from the line, and measured it again.  It had no effect.  So it
appears to be coming from the phone company that way.  I called 611, and
she said to call during regular business hours and ask for a tech.  She did
say that they had installed some new equipment recently, and that might
be why.  Anyway, is this normal, or is there something wrong somewhere??

I remember a few years ago, measuring this same phone line, that while the
phone was on-hook, it sat steadily at 50v, not varying unless the phone
was taken off-hook.