Tuner wrote:
> I'm attempting to construct a control box into which 6 separate
> phones will be connected with normal RJ11 jacks. I'd like to control
> each phone's ringer separately - no voice line, just make the phone
> ring.
>
> These will all be standard desk telephones, US issue. I understand
> that I need approximately 90 volts AC to drive the ringers, but I
> can't seem to find out the required amperage so I can purchase the
> appropriate transformer. Is anyone familiar with the particulars?
>
> Yes, I've heard of the Tele-Q device, but we're working on no budget
> and want to control 6 phones, not just one.
>
> TIA!!
>
> Tuner
on old style phones on the bottom was printed a ringer equivalence number.
it usually was less then 1. for example .8 or .3
when ordering phone lines for special purposes such as broadcast use the
telco demanded equipment type number and ringer equivalence.
the ring currrent would energize the solenoid which beat the clapper
against
the bells.
you best bet is to measure the current draw of you phones when they ring.
please exercise caution as 90 vac can be lethal.
today's phones which use electronic sound generators are a miniscule load
as
compared to the old phones.
more info on ringer equivalence is here
http://www.answers.com/topic/ringer-equivalence-number
an even more informative site:
http://www.affordablephones.net/theringer.htm
while i can think of several ways to produce 90 vac i can't think of any
that are intrinsically safe. i might use an audio oscillator driving an
audio power amp to provide power at 20 to 30 Hz.
more probably i would fake the phone operation and play a sound effect
over
the PA system.
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