Hi All

Can you please give me a circuit diagram to (Get and inject an audio signal at the same time from/to phone Line)

I went through the http://www.tkk.fi/Misc/Electronics/circuits/teleinterface.html article, but I am confused.

Thank you

 

Make sure your device has a characteristic impedence of 600 ohms and a bandwidth of 300-3300 Hz . Make sure it can withstand 90Vac ringer voltage on the signal line. If it is to run off the phone line voltage, make sure it runs on 48Vdc.

Then simply connect it in parallel with the phone line.

 

Most telcos frown upon installing anything in their line without first isolating it with a 600ohm:600 ohm transformer.