spamtrap1888 writes:

On Aug 7, 11:08=A0am, 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.

Depends on the source. Large CO's had motor-driven 20Hz generators.
C.P Stocker invented the SubCycle, a no-moving-parts 20 Hz generator
that replaced all but the largest m-g sets.

In any case, the ringer was not picky about waveform.




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