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LINEAR INTEGRATED CIRCUITS
TELEPHONE SPEECH CIRCUITS
The LS285 and LS285A are monolithic integrated circuits for replacement of the hybrid circuit (2-4 wire interface) in conventional telephones interfacing the two transducers to the line and providing a controlled amount of sidetone. The same type of transducer can be used for both transmitter and receiver, usually a 3500 dynamic type. By sensing the line current, LS285 and LS285A adjust the gain in both directions to compensate for line attenuation. Output impedance can be matched to the line, independent of transducer impedance. The LS285 and LS285A are packaged in a 14 lead dual in-line plastic package.
LS285A Datasheet
