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Audio Circuits:  Intercom Circuits
Intercoms:  #'s - O      P - Z
Amplifier -- Main Page  
Last Updated on: Friday, March 12, 2010 12:07 PM

 

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Party Line Intercom  - (diagram added 6/03)

Phones as an intercom - (electronic design added 6/07)

Phones as Intercoms - (electronic design added 6/07)

Phones become an Intercom - ASCII format (added 8/03)

Practical Intercom - Electronic circuit (Tony van Roon's electronic design 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....(added 4/05)

Simple Intercom - The simplest possible way to make an intercom is by connecting two loudspeakers in series with a battery, as in the circuit shown here.  One of the speakers must be at a remote location. Sound waves impacting on either of the loudspeakers induce a current in its coil which is translated back into sound by the other speaker. Yes, a loudspeaker works just fine as a microphone....(electronic design added 6/07)

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 - 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..... (added 5/02)

Use old Phones as an Intercom - ASCII format Now here's some logic that should work fine with the right zener and the right resistors and a couple of cheap npn's 2n2222A's or 2n3904's (06's?). If you get close to 25 volts with the new smart test boxes, a 20 volt Z may work fine. Choose R1 to limit current through Z and have enough left to turn on npn1 just enough to deprive npn2, choose R2 for that, and you will need to add a resistor R3 to protect the LED from overcurrent as needed, depending on the phone system you have!  (added 1/07)

 

 

Intercoms:  #'s - O      P - Z

 
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