Constant current line circuit with class features
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Mar 8, 2005
Grant Date -
Oct 18, 2001
app pub date -
Mar 30, 2001
filing date -
Mar 31, 2000
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A line circuit utilizing a differential amplifier whose output is regulated to zero volts D.C. (when the subscriber's set is off-hook) by a negative feedback circuit, for controlling a voltage controlled power supply which provides a constant current feed to the subscriber's loop. The differential amplifier also transmits audio signals received from the subscriber's loop directly to a PABX via an unbalanced terminal. When the loop range exceeds a predetermined threshold, the circuit reverts to a voltage feed operation thereby allowing operation over long loop lengths and the ability to provide on-hook CLASS services.
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