Northern Telecom Limited

Nadir Nizamuddin

Alan S Chapman

Terence N Thomas

David J Robertson

Alan M Redmond

Ronald J Maginley

John W Williams

Robert S Morley

Timothy J Littlewood

Anthony Yung

Bora Biray

Johann D Ramsaran

A key telephone system includes a plurality of ports linked by port associated bidirectional communication channels which are synchronously switched by transferring bit states between ones of the channels to provide communication paths between the ports as directed by a central processor. The ports are also linkable to and via the central processor by port associated message channels. An interface circuit is responsive to the central processor and message channel signals for regulating flow of messages received by the central processor and for effecting single and plural channel distribution of messages from the central processor. The message channels permit telephony operating features and functions to be provided either within the central processor or by appropriate apparatus means being connected at any of the ports. In such a telephone system at least one of said apparatus comprises a telephone station apparatus and another of said apparatus comprises a feature host apparatus. The telephone station apparatus has a plurality of functions stored therein and said feature host apparatus has a plurality of feature modules stored therein. Each such feature module comprises instructions for invoking a corresponding set of functions at said telephone station apparatus by means of an exchange of signalling and supervision messages between said feature host apparatus and said telephone station apparatus. The functions invoked provide the feature selected by a feature request action of a user at said telephone station apparatus.

Digital key telephone system

Relocation and/or replacement of terminal apparatus in telecommunications systems including, but not necessarily limited to, key telephone systems, usually entails reassignment of administration data; for example, features. When a station or terminal apparatus is moved physically from one port to another within a telecommunications system which comprises a plurality of ports connected to a central processor, interface means operative on initial connection of said terminal apparatus transmits to the central processor an identifier unique to such terminal apparatus within such system. The central processing means has storage for each said identifier together with administration data specific to said terminal apparatus and the number of the port to which said terminal apparatus set is connected. Following receipt of an identifier, the central processor updates said storage means to assign said administration data corresponding to said identifier to the present port.

A key telephone system includes a plurality of ports being linked by port associated bidirectional communication channels which are synchronously switched by transferring bit states between ones of the channels to provide communication paths between the ports as directed by a central processor. The ports are also linkable to and via the central processor by port associated message channels. An interface circuit is responsive to the central processor and message channel signals for regulating flow of messages received by the central processor and for effecting single and plural channel distribution of messages from the central processor. The message channels permit telephony operating features and functions to be provided either within the central processor or by appropriate apparatus means being connected at any of the ports.

The invention provides a circuit and method for the time-sharing of a DTMF tone receiver. A DTMF receiver has its input terminal connected to a common output terminal of a pair of transmission gates, each gate having an input terminal connected to a respective source of DTMF signals. A control circuit provides switching signals to the transmission gates to cause their input terminals to be connected alternately to the input terminal of the receiver at a predetermined rate until the receiver detects a tone signal on at least one of the input terminals of the gates. The control circuit includes circuitry responsive to the initial tone detection for inhibiting the further generation of switching signals until the tone detection by the receiver has been completed.

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Kanata, Canada

Nadir Nizamuddin