US 4,608,686 AGranted

Two wire voice and data subscriber loop

AssigneeMitel Corporation

InventorJohn A. Barsellotti

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Abstract

A circuit for transmitting both voice and data at the same time between a subscriber's set and a switching exchange via a bidirectional two wire link. The invention is comprised of a subscriber's set adapted to generate and receive baseband voice signals and data signals, a circuit for 100% amplitude modulating the generated data signal on a carrier signal having its lowest sideband after filtering above the voice signal base band, a circuit for applying the voice signals and modulated carrier to a two-wire subscriber's line, a circuit for separating the voice signals and modulated carrier, and a circuit for demodulating the digital signal and applying the digital signal to control circuits of a switching exchange. Voice signals are applied to voice handling circuits such as the voice switching circuits of the switching machine.

Claims27

Dependent claims

A bidirectional two wire combined voice and data transmission system comprising:

(a) a telephone switching exchange including voice signal switching means and a bus system to which a switching exchange controller is connected, the voice signal switching means having a defined audio frequency transmission bandwidth,
(b) one or more subscribers' sets for generating audio frequency analog signals for transmission to the switching exchange,
(c) means associated with each subscriber's set for generating serial digital signals for transmission to said switching exhcange,
(d) means for amplitude modulating a carrier signal with said digital signals, the carrier signal being at a frequency higher than the upper limit of said defined bandwidth, and at least twice the highest frequency of said analog signals,
(e) means for combining the modulated digital signals and said analog signals,
(f) one or more two wire subscribers' lines interconnecting the subscribers' sets and said switching exchange,
(g) means for applying the combined signals to one end of each of the subscribers' lines,
(h) means for receiving the combined signals at the switching exchange, including multiplexing and demodulating means for reconstructing the digital signals, and applying them to said bus system, and including means for filtering the analog signals and applying them to the voice signal switching means.

5 more elements

A bidirectional two-wire combined voice and data transmission system for subscribers' sets comprising:

(a) one or more subscribers' sets adapted to generate and to receive baseband voice signals and data signals via a two-wire bidirectional link,
(b) means for amplitude modulating the generated data signals on one or more carrier signals having their lowest filtered sidebands above the voice signal baseband,
(c) means for applying said voice signals and modulated carrier together on one or more two-wire subscribers' lines connected to respective ones of the subscribers' sets,
(d) means at a switching exchange for separating the voice signals and modulated carrier signals, and for applying the voice signals to voice signal switching paths of the switching exchange, and
(e) means for multiplexing and demodulating the data signals and applying the demodulated data signals to control circuits of the switching exchange.

2 more elements

Dependencies are inferred from the claim text.