On Aug 7, 11:08*am, David Lesher wrote:

If you understand anything about telephone equipment, your line sits
at 48VDC when the phone in on hook, (hung up). When it rings, an AC
voltage, usually at a frequency of 20HZ is superimposed on the line.

Well, ~130VAC atop the -48V.


As I recall from days gone by, the ringing current waveform was 130 Vp-
p. It was also far from a perfect sine wave, so what the rms voltage
was was anybody's guess.