Mitel Corporation

Trillium Telephone Systems Inc.

Brian J Pascas

Graham A Neathway

Paul S Wilker

Robert K Blackhall

Gordon D Benning

Brian J Vaughan

A service circuit for a local telephone line in a building wired with quad telephone conductors, including a tip and ring lead pair continuous with a subscriber's line connected to a remote switching machine, and a service lead pair within the building. A special service circuit is connected to the tip and ring lead pair and to the service lead pair. A control unit is also connected to the tip and ring lead pair and the service lead pair for receiving signals over either the tip and ring pair or the service lead pair from a telephone connected to the local line, and for generating a predetermined special service circuit enabling signal on the service lead pair. The enabling signal is received by the special service circuit which implements one or more special services in response thereto. The control unit also applies operating power to the service lead pair. The special services implemented include intercom, paging, tone ringing, etc. The control unit also provides power, control, rapid dialing signals, etc.

Home communications and control system

A telephone system used in the home which provides special services such as intercom, paging, remote turn on or off of power contacts, audio monitoring, etc. A central control is interposed between the subscriber's line and the local wiring in his home, or is connected in parallel thereto. One or more telephone subscriber sets are plugged into the wiring as usual, contacting the tip and ring leads. In the present invention, remote special service circuits are plugged into the telephone line, contacting the remaining two conductors, referred to below as the black B and yellow Y leads. Each of the remote special service circuits has a specialized function, e.g., a typical circuit will have a speaker, an amplifier for driving the speaker, and a circuit for enabling the amplifier and connecting it across the black and yellow leads once an address has been received on the black and yellow leads. Preferably, a housing containing this type of module has a socket into which a subscriber's telephone set can be plugged, and the circuit itself is connected to the local telephone line, connecting the telephone set directly or via a switch to the tip and ring leads and connecting the amplifier and enabling circuit to the black and yellow leads. Each telephone set thus will have a local speaker associated with it. However in a typical installation there could well be special service circuits of the latter type connected to the local telephone line without having a telephone set connected into it, or located adjacent thereto.

Home telephone exchange

A dial pulse detection circuit for partial correction of grossly distorted line current dial pulses, which provides square wave output signals for use by later timing detection circuitry. To detect such dial pulses, the present invention establishes an upper and a lower detection threshold. For a valid dial pulse to be detected, the line current must drop through both thresholds, and then rise again through at least the lower threshold. With the provision of a detection delay following detection of the leading edge of a dial pulse, the presence of a valid dial pulse can be registered. The present technique used in detecting the presence of dial pulses substantially reduces the chances of rejection of a valid dial pulse which has a grossly distorted waveform.

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Kanata, Canada

Brian J Pascas