Plantronics, Inc.

Gary L Sanders

Robert J Bernardi

Frederick P DeKalb

Jeff M Wimsatt

An electronic telephone set for use with a telephone headset receiver/transmitter apparatus is disclosed. The telephone set is line-powered, and is capable of transmit muting, last number re-dial, and memory dialing. The volume of the received voice signal is controllable by a user, and a visual indication of the volume setting is provided. The receiver and transmitter amplifiers includes circuitry for compensating for the frequency response characteristics of two or more headsets, the compensation circuitry being selectively and automatically engaged by means of a programmable connecting jack. The design of the telephone is such that it consumes very little power, especially during 'on-hook' operation. Moreover, an electrical storage device is employed to provide continuous operational power to the dialer circuitry and electronic hook-switch control circuitry, so that the telephone set retains its dialing memory when not in use. Bell tap suppression circuitry is included to prevent the ringer from responding to sporadic voltage transients on the transmission lines, allowing the telephone can be installed in parallel with other phones.

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Saratoga, CA, United States of America

Gary L Sanders