US 4,173,714 AGranted

Communication circuit with combined power feed and data transmission over a phantom channel

AssigneeTIE/Communications, Inc.

InventorsAlan Bloch, Frank A. Coviello, Ira Guzik, Candido Puebla

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Abstract

The disclosure relates to a four conductor circuit arrangement providing two communication channels between a control unit and a terminal device. Power feed and bi-directional signalling are accomplished simultaneously over the same four conductors used for the two commmunication channels without interference. The signalling from the control unit to the terminal is accomplished by means of a voltage modulator circuit in the control unit by which voltage pulses are transmitted via a phantom circuit arrangement over the four conductors to the terminal unit. The voltage pulses are sensed from the phantom circuit in a data receiver which is located at the terminal unit. Connected to the phantom circuit in the terminal unit is a voltage regulator circuit which receives power from the control unit via the four conductor phantom circuit interconnecting the control unit and the terminal. In series with the voltage regulator circuit is a constant current sink and an inductor. A current modulator circuit is provided in parallel for impressing current data pulses generated in the terminal onto the phantom circuit, which are, in turn, received by a receiver circuit in the control unit. A preferred data format is disclosed as a method for transmitting information between the control unit and the terminal. The preferred embodiment for the disclosed four conductor communication circuit and the disclosed data format is in a key telephone system in which the control unit is a station card in a key service unit and the terminal is a key telephone station set.

A circuit arrangement providing first and second communication channels, power feed and bi-directional signalling between first and second equipment units comprising,

four conductors the ends of which are connected between the first and second equipment units, a first pair of said conductors providing a first information channel between the first and second equipment units, and a second pair of said conductors providing a second information channel between the first and second equipment units,
first and second transformers for inductively coupling associated first communication channels in the first and second equipment units via said first conductor pair, each of the windings of said first and second transformers connected to said first conductor pair having a center tap connection,
third and fourth transformers for inductively coupling associated second communication channels in the first and second equipment units via said second conductor pair, each of the windings of said third and fourth transformers connected to said second conductor pair having a center tap connection,
means in the first equipment unit connected via said center taps of said first and third transformers to said first and second conductor pairs at the first equipment unit for
(a) applying voltage to said four conductors,
(b) applying voltage-modulated data signals to said four conductors for transmission from the first equipment unit to the second equipment unit, and
(c) receiving current-modulated data signals transmitted from the second equipment unit on said four conductors, and means in the second equipment unit connected via said center taps of said second and fourth transformers to said first and second conductor pairs at the second equipment unit for
(a) receiving and regulating said voltage applied to said four conductors in the first equipment unit and applying said voltage to power the second equipment unit,
(b) receiving voltage-modulated data signals on said four conductors from the first equipment unit, and
(c) applying current-modulated data signals to said four conductors for transmission from the second equipment unit to the first equipment unit.

7 more elements

Facts

Application

05/803,243Filed 3 Jun 1977

Granted

6 Nov 1979

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

H04L 5/20
Arrangements affording multiple use of the transmission path: using different combinations of lines, e.g. phantom working
H04B 3/44
Details: arrangements for feeding power to a repeater along the transmission line
H04M 9/003
With subscriber controlled access to a line, i.e. key telephone systems: transmission of control signals from or to the key telephone set;…
H04Q 5/04
With direct connection for all subscribers, i.e. party-line systems: signalling by currents in one or other or both line wires or additional wires

Abstract

Claims12