Telephone status monitor circit
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Sep 2, 1980
Grant Date -
N/A
app pub date -
Dec 4, 1978
filing date -
Dec 4, 1978
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A telephone status monitor circuit for determining the on/hook and off/hook conditions of a telephone connected across standard tip and ring terminals of a telephone system. The telephone status monitor circuit includes a charging circuit, in the form of a series combination of a capacitor and a resistor, which is adapted to be alternately and periodically switched in and out of circuit with the tip and ring terminals. When the charging circuit is in circuit with the tip and ring terminals, the capacitor is charged to the value of the voltage across the tip and ring terminals. When the charging circuit is out of circuit with the tip and ring terminals, the charging circuit is coupled to additional circuitry which examines the value of the voltage across the capacitor. If the value of the voltage across the capacitor corresponds to an on/hook condition, a first output signal is produced by the additional circuitry. If the value of the voltage across the capacitor corresponds to an off/hook condition, a second output signal is produced by the additional circuitry.
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