U4055B1
Description
The U4055B electronic speech circuit is a linear integrated circuit for use in telephone and other line fed terminal equipment. It replaces the mon speech circuit with carbon microphone, hybrid transformer, sidetone equivalent and ear protection rectifiers. A low-cost electrodynamic transducer is used as the earphone. It contains all ponents necessary for amplification of signals and adaption to the line.
Features
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D An electronic circuit replaces the microphone hybrid transformer D Symmetrical input for dynamic or piezo microphone D High performance through the use of dynamic transducers as the earphone (non-linear distortion 2 %)
D DTMF interface with muting D Supply voltage for dialer D High range of line feeding current D Input resistance independent of line current and sidetone suppression circuit. D Built-in ear protection by earphone voltage limiter D Operation possible from 8 m A x
D Automatic line loss pensation
U4055B1: High level mute; U4055B: Low level...
