Require a simple telephone line simulator!

[UroBoros]

Hai

For developing a DTMF trigger through phone lines,I am looking for a simple telephone line simulator.

requirements.


1 . line voltages 48V ON hook and 10-12V OFF hook.
2. ringing signal to be generated at will .

3. Dial Tone ,optional not must

Links or suggessions or circuits. please.

Thanks a lot ..
Looking forward for replies


picstudent

 

[IanP]

Try this one ..
It is not as simple as it sounds ..

Regards,
IanP

 

[UroBoros]

Hai

Thanks IanP for the circuit,But I am afraid it is too complex for my time available for this purpose. Let me ask you one thing.


if I created a 60volts dc power supply and connect the phone through a series dropping resistor(Value by trial and error),I can simulate the dc voltage changes when the phone is picked up. (45volts to 12volts)

Then next problem is how to generate theringing signal and enforce the same into telephone line.

No other feature is required.

My MCU unit needs to see the line status .ON hook or OFF hook(By a comparator). Also it have to count the rings . So voltsge and rings are only needed.

thanks
picstudent

 

[IanP]

I thought so ..
Here you will find much easier "telephone ringer":
(Methods for generating good ring voltage)
**broken link removed**

Regards,
IanP

 

[marwan naboulsi]

telephone hook off circuit

 

[eng_ahmed22]

hi Picstudent
see the next link. it decribe a home made PBX. to build a PBX it needs ring, dial ton, DC voltage for the speech cuircuit in any telephone
i think this will help u:
http://wandel.ca/homepage/pbx.html
salam
Ahmed
www.i-g.org