ckt-boarder
New Member
I was recently replacing a phone jack in my living room, but when I plugged in the phone there was no dial tone. It's my understanding that the "on hook" voltage is about -40VDC between tip and ring, but when I measured the pins with my multimeter it read 0VDC. To rule out a faulty multimeter, I then tested a jack which I know works, but again I read 0V. I then found the wiring block in my basement and measured between the tip and ring and this time read -46VDC. I suspect the jack I wanted to replace is probably disconnected somewhere inside the wall, but my question is, what about the jack that I know works? Why would it read 0V and not -40V? Does this have something to do with the impedance of the wires or something else?