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Elektrisk Bureau PAX SXS with drums

Started by dsk, September 05, 2013, 08:45:46 AM

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dsk

This design are from approx wwi but it works, and are just implemented as my home telephone system. The outbound calling are still a problem, and does only work on the shortest lines. My son noticed at once the different ringing, 25Hz vs 20Hz :-)

dsk

dsk

The ringing tone are depending on the ringer current, my "modern" phones with more than 1000 ohms ringers does not draw enough current.  That is a problem I never have considered as a possible problem!

dsk

dsk

How does the ring look?
Tried to catch some data via the PC sound card and the Visual analyzer (freeware), and here is the ring, generated by a vibrator, the cadence is controlled by a relay and capacitor:
dsk

dsk


dsk

Even the first trunk failed, but I have redesigned it and for the moment this is working for outgoing calls.

dsk

I learn something all the time, but that the ringing sounds different depending on the other end.

Here I have first an electronic ringer from 1980, then 2 old phones so they will draw pretty high REN load, and at last no load.
https://soundcloud.com/d_s_k-2/depending-on-ringerload
dsk