🚀 go-pugleaf

In article <1988Sep22.060244.3959@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes:
> For that matter, I seem to recall seeing mention that some old dial
> phones worked better with one polarity than with the other -- with
> annoyances like slight bell noises during dialing if you got the
> polarity wrong -- but I've never confirmed this personally.

	It is indeed true that some ringer designs are prone to "bell tapping"
during dialing.  While ringers are designed for operation on 20 to 30 Hz,
some models are sensitive to the large DC transients which occur during
rotary dialing.  These ringers are "biased" using a permanent magnet and
a bias spring, therefore rendering them somewhat polarity sensitive to a
DC pulse.
	The most expedient way to eliminate bell tapping within a telephone
set is to make certain that one ringer lead is connected to a break contact
on the switchhook which disconnects the bell when the set is off-hook.
For permanently bridged extension ringers, the bias spring tension can
also be increased to correct the problem.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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