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Class Information
Number: 379/236
Name: Telephonic communications > Plural exchange network or interconnection > Interexchange signalling > D.c. signalling over trunk
Description: Subject matter wherein the control or supervisory signal is represented by the presence or polarity of the current or voltage in a particular circuit.
Sub-classes under this class:
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7231211 |
Apparatus and method for monitoring a trunked radio communications system |
Jun. 12, 2007 |
| 6337906 |
Apparatus and method for coupling an automated attendant to a telecommunications system |
Jan. 8, 2002 |
| 6275578 |
Method and apparatus for providing back-up, in-band signaling in a communications network |
Aug. 14, 2001 |
| 5263081 |
Method and apparatus for providing on-hook transmission for digital loop carrier channel units |
Nov. 16, 1993 |
| 5247574 |
Adaptive no balance DX signalling circuit |
Sep. 21, 1993 |
| 5222129 |
Telephone charging signalling detector suitable for central office line interface circuits |
Jun. 22, 1993 |
| 4907261 |
Universal DC signalling detector |
Mar. 6, 1990 |
| 4852157 |
Multi-task state machine signalling translator |
Jul. 25, 1989 |
| 4815124 |
DX circuit |
Mar. 21, 1989 |
| 4734935 |
Communication system with remotely controllable signal receiving means |
Mar. 29, 1988 |
| 4563547 |
Loop-start/ground-start line interface circuit |
Jan. 7, 1986 |
| 4126765 |
Detector circuit for sensing battery polarity and loop closure |
Nov. 21, 1978 |
| 4110565 |
Duplex telephone signalling system |
Aug. 29, 1978 |
| 4065643 |
Communication facility integrity checking arrangement |
Dec. 27, 1977 |
| 4058685 |
Interoffice loop supervision arrangement |
Nov. 15, 1977 |
| 4037120 |
Electronic dipole for looping a telephone line |
Jul. 19, 1977 |
| 4002850 |
Trunk adapter |
Jan. 11, 1977 |
| 3940570 |
Apparatus for combining a central telephone trunk line with a customer telephone trunk line |
Feb. 24, 1976 |
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