Intercommunication b/w two headsets using telephone lines

[rajashekharreddym]

hi,
I want to communicate with another module using Headset and MIC using Telephone line interface over a distance of 150M.
For that what are the modules to be used to communicate between the Headset-1 and Headset-2 using telephone wire Interface over a distance of 150 meters.
My communication type is Full duplex, and audio communication.
What are the Power supplies should I use?.
My application is similar to INTERCOM application.
I dont want to use the telephone lines, i want to make communication media that is equivalent to telephone, with out ringer and dialer.
Please tell me the parts to be used, and send some schematics for the above query.

rajashekhar.m@icsglobal.biz
09246362541

 

[FvM]

See a basic intercom design in the attachment. It uses an AGC microphone amplifier, a headphone amplifier and an active hybrid circuit. Originally it has been using a shielded twisted pair with one wire utilized for the power supply and an additional beeper/light call sign. But these points may be adapted for your purposes. Also a two wire power supply through an inductor would be basically possible.

 

[rajashekharreddym]

See a basic intercom design in the attachment. It uses an AGC microphone amplifier, a headphone amplifier and an active hybrid circuit. Originally it has been using a shielded twisted pair with one wire utilized for the power supply and an additional beeper/light call sign. But these points may be adapted for your purposes. Also a two wire power supply through an inductor would be basically possible.

hi,
can u send the attachment file to me. and how to build tha hybrid circuit?

 

[FvM]

can u send the attachment file to me

Can't you download it from edaboard?

In telephones, the hybrid is formed by a transformer circuit, I used a simple OP ciruit. For it's correct operation, the 820 ohm line termination in one peer is mandatory.

For the hybrid operation principle, see: Hybrid coil - Wikipedia, the free encyclopedia