🚀 go-pugleaf

In article <5651@internal.Apple.COM>, ems@Apple.COM (Mike Smith) writes:
> Vague memory from too many decades ago... I think the ring signal is 
> pulsed DC at about 50 V and the current is 'all the inductor can carry'...

	Ringing voltage is typically 20 Hz AC @ 105 volt RMS upon which is
superimposed -50 volts DC (with respect to ground).  The DC component is
present to facilitate operation og a "ring-trip" relay or solid-state
circuit.

	The telephone ringing supply is traditionally current limited to
about 100 mA by a resistance lamp (i.e., ballast lamp).  Resistance lamps
are still used in much ESS apparatus due to their inherent simplicity and
reliability.  Newer ESS apparatus uses solid-state circuits for ringing
supply current limiting.

	Ringing voltage is not applied to a telephone line through an
inductor, so there is no current limiting by that means.

<> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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