Telephone amplifier with switchable gain control
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United States of America Patent
Stats
-
Sep 20, 1988
Grant Date -
N/A
app pub date -
Feb 18, 1986
filing date -
Feb 18, 1986
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
An amplifier for controlling the volume in a telephone instrument of the general type including coin-operated and pay type telephone instruments is enclosed in the telephone housing and provides a number of discrete, predetermined amplification levels selectable by operating a push-button switch also located in the housing so that its plunger extends through an opening in the telephone instrument face. The amplification level is automatically restored to a volume associated with a normal hearing sensitivity at the start of a new call and a dial shunt circuit suppresses the DTMF tones heard by a user when tone dialing is used.
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Family
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Cited Art Landscape
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