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remote telephone ringer

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MYVALK

New Member
i need to build, and be shown how to hook up, a remote phone bell, so i can hear the phone when im outside of my office.
any ideas?
thanx in advance.


wow... bigger than i thought hahaha
 

Leftyretro

New Member
MYVALK said:
i need to build, and be shown how to hook up, a remote phone bell, so i can hear the phone when im outside of my office.
any ideas?
thanx in advance.


wow... bigger than i thought hahaha
Just use a normal phone hooked up outside your office?
 

blueroomelectronics

Well-Known Member
You've got to be careful what you connect to the phone lines. It's better if you buy such a device and most likely cheaper than the parts you'll need.
 

crutschow

Well-Known Member
Most Helpful Member
MYVALK said:
but.. if i wanted to build my own, what would it entail?
Bill is right. Why reinvent the wheel?

The phone ring in the U.S. is a 20Hz, 75VAC signal which is riding on -48V DC. You need to detect the AC (without drawing any significant DC current) and convert it into a higher frequency audible signal (20Hz being pretty well inaudible). The circuit to detect this must be isolated from ground. The equivalent load for 1 ringer is defined to be an 8uF cap in series with 6930 ohms. It's good practice not to exceed that load when connecting to the phone line.

I made one many years ago using a unijunction transistor oscillator powered from the ring signal to generate high frequency pulses (a kHz or so) which drove a small speaker. Made kind of a ratty sound, but you knew when the phone was ringing.

Still want to do it?
 
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