Telephone interface circuit
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United States of America Patent
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May 10, 2011
Grant Date -
Feb 14, 2008
app pub date -
Jul 6, 2006
filing date -
Jul 6, 2006
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A telephone interface circuit comprising a speech circuit, a control circuit turning on upon receiving a supply of a forward direction trigger current so as to connect first and second telephone lines and the speech circuit, and going off upon receiving a supply of a reverse direction trigger current so as to disconnect the first and second telephone lines and the speech circuit, a capacitor charging and discharging charge supplied from the first telephone line, and a hook switch supplying charge accumulated at the capacitor when off-hook to the control circuit as a forward direction trigger current, and supplying charge discharged from the capacitor when on-hook to the control circuit as a reverse direction trigger current.
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