2 Line Intercom With Telephone Line Changeover Circuit: The circuit presented here can be used for connecting two telephones in parallel and also as a2-line intercom. |
Creating your Own Telephone Ne2 Rk: you can easily create your own intercom system using two telephones, a 9-volt battery (or some other simple power supply) and a300-ohm resistor |
Intercom Preamp: a convenient way of making an intercom is to use a loudspeaker as a microph1- |
Two Line Intercom With Telephone Line Changeover Circuit: The circuit presented here can be used for connecting two telephones in parallel and also as a2-line intercom. |
Using the Comrex Hotline or Vector on a Dry Pair: how to use simple pair of wires with no voltage, ringing signals to interconnect normal Telephone line devices. |