Electrical Communication is a free textbook on the basics of communication technology. See the editorial for more information....

Common-Battery Telephone Sets

In the common-battery telephone system, one battery at the central office supplies the direct current to all transmitters in use at a given time; hence, the term common battery. The historyref.3 of this type of set is of interest, many circuits, some of questionable merit, having been developed.ref.2,3,4,5

Common-battery telephone circuits may be classified as sidetone circuits or as antisidetone circuits. With the first type, considerable energy is transferred from the transmitter to the receiver, and thus a sound actuating the transmitter is plainly heard in the associated receiver as sidetone. The antisidetone circuit greatly reduces this effect.

Last Update: 2011-05-30