US PATENT SUBCLASS 379 / 377
.~ Using line or loop condition detection (e.g., line circuit)

Current as of: June, 1999
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379 /   HD   TELEPHONIC COMMUNICATIONS

350  DF  SUPERVISORY OR CONTROL LINE SIGNALLING {5}
377.~ Using line or loop condition detection (e.g., line circuit) {7}
378  DF  .~.~> With current controlling electromagnetic core device (e.g., Hall-effect device)
379  DF  .~.~> With optical link between line and switching system
380  DF  .~.~> By bridge circuit
381  DF  .~.~> Busy test or make busy
382  DF  .~.~> For ring trip or polarity reversal detection
383  DF  .~.~> Of plural lines {1}
385  DF  .~.~> Relayless

DEFINITION

Classification: 379/377

Using line or loop condition detection (e.g., line circuit):

(under subclass 350) Subject matter in which the supervisory or control signal is generated in response to an electrical state of a subscriber circuit.