[SML] Telephone line simulator

[Steven Santos]

With  Digium cards on ebay for $30, wouldn't the easy answer be an old box
with a Digium card and a copy of Asterisk?

IIRC, the ring is configurable within  Asterisk and it gives you a lot of
scripting options.  I am sure a DMX trigger could be hacked.

On Sat, Apr 11, 2020 at 7:22 AM Dan Sheehan via Stagecraft <
stagecraft at theatrical.net> wrote:

> thanks Jerry
>
> * doorbell transformer would probably work,
> or any small thing (wall wart?) with a very roughly 1:10 ratio (ie made
> for 120V to ~12V AC),
>  provided the 20Hz source (amp) can drive the low end of it
>
> On Sat, Apr 11, 2020 at 1:58 AM Jerry Durand via Stagecraft <
> stagecraft at theatrical.net> wrote:
>
>> For the low of budget people, if you just need to generate ring you can
>> do so with bits you might have laying around.
>>
>> You'll need:
>> An audio source for 20Hz sine wave, pulsed in whatever cadence you want.
>>
>> An audio amplifier, I used a Radio Shack PA amplifier for one setup.
>> Doesn't need to be quality, just function.
>>
>> If the amplifier has 70 volt line out, you can skip the transformer in
>> the next line.
>>
>> * >An 8 ohm to 70 volt PA transformer. <*
>>
>> A blocking capacitor, steal a RUN capacitor from an induction motor
>> you're not using.
>>
>> The capacitor isn't strictly needed, but does limit current.
>>
>> Circuit is audio source > amplifier > 8-transformer-70 > capacitor in
>> series with one lead > telephone.
>>
>> Be sure and cut the audio when the actor picks up, you don't want to
>> blast his ear with the ring signal.  Maybe remove the speaker from the
>> phone.
>>
>> Experiment to find what works well with your phone and gear.
>>
>>
>>
>> ---
>> Jerry Durand, Durand Interstellar, Inc. +1 408 356-3886
>> <http://www.DurandInterstellar.com>www.DurandInterstellar.com &
>> <http://www.DurandInterstellar.ru>www.DurandInterstellar.ru
>>
>>>
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>
>
> --
> ...Dan Sheehan
> Fixer of things that break
> TD Walpole (MA) Footlighters
>
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