Party Line Intercom :  (diagram added 6/03)

Practical Intercom:  Electronic circuit (added 9/04)

Remote Control using Telephone:  Here is a tele-remote circuit which enables switching "on" and "off" of appliances through Telephone lines. The circuit described here can be used to switch up to nine appliances (corresponding to the digits1 through 9 of DTMF the Telephone key-pad). The Telephone can be used to switch on or switch off the appliances also while being used for normal conversation. (added 4/05)

The Link Telephone Intercom Every Home Should Have One!:  The Link circuitry is simple and efficient, employing just two ICs, half a dozen transistors, and a handful of garden variety components. It all runs on 12 volts and is easily assembled. You can have your own home intercom between the kitchen, the garage, the rumpus room and at your poolside ‘barby’ and all for less than $100! The “Link” intercom....   (added 10/05)

Two Line Intercom Cum Telephone Line Changeover Circuit:  (circuit / schematic design added 6/06)

Two line intercom plus a telephone changeover switch #2:  The circuit presented here can be used for connecting two telephones in parallel and also as a 2-line intercom.
Usually a single telephone is connected to a telephone line. If another telephone is required at some distance, a parallel line is taken for connecting the other telephone. In this simple parallel line operation, the main problem is loss of privacy besides interference from the other phone. This problem is obviated in the circuit presented here..... (added 6/06)

Two Line Intercom Plus a Telephone Changeover Switch:  The circuit presented here can be used for connecting two telephones in parallel and also as a 2-line intercom.
Usually a single telephone is connected to a telephone line. If another telephone is required at some distance, a parallel line is taken for connecting the other telephone. In this simple parallel line operation, the main problem is loss of privacy besides interference from the other phone. This problem is obviated in the circuit presented here..... (added 9/06)

Two Line Intercom with Telephone Line Changeover Circuit:  The circuit presented here can be used for connecting two telephones in parallel and also as a 2-line intercom.
Usually a single telephone is connected to a telephone line. If another telephone is required at some distance, a parallel line is taken for connecting the other telephone. In this simple parallel line operation, the main problem is loss of privacy besides interference from the other phone. This problem is obviated in the circuit presented here..... (added 6/06)

Use old Phones as an Intercom:  ASCII format (added 1/07)