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?

__________________
Measurement changes behavior

 

Radio Shack sells a remote ringer at http://www.radioshack.com/product/in...entPage=search that should do just what you want.

 

thats it . thanx.

 

but.. if i wanted to build my own, what would it entail?

 

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.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

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?

 

8uF, here it's 2uF

 

ok guys, ill take your advice and radio shack it.

thanx again.