Bell Telephone Laboratories

At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Edward H Hafer

Thomas L Hiller

David A Pierce

James M Johnson, Jr

Christopher G McHarg

Dennis L DeBruler

Scott W Pector

William J Klinger

Douglas A Kimber

A switching system including a number of switching modules each having a plurality of access ports. Incoming and outgoing packet channels are extended between each switching module and an inter-module packet switch. Each of the switching modules includes both a packet switching unit and a circuit switching unit for switching information to and from the access ports. Each switching module further includes a control unit that controls the switching units and that generates inter-module control packets, and a communication interface that transmits inter-module control packets generated by the control unit on the incoming packet channel to the inter-module packet switch. The communication interface also transmits inter-module control packets received on the outgoing packet channel from the inter-module packet switch to the control unit. The inter-module packet switch concurrently packet switches inter-module control packets received on a number of the incoming packet channels, via mutltiple independent paths to a number of the outgoing packet channels.

Control information communication arrangement for a distributed control

Communications between stations served by different time slot interchangers (TSI) nodes in a telecommunications network are made possible without the use of either an intermediate stage of time multiplex space division switching or central time slot allocation by an arrangement in which each TSI node is linked to every other node by a patent in which each nodes time slots are 'broadcast' to every other node in the network. Each time slot word includes a data or address (D/A) field and a status (ST) field. The D/A field of the time slot word is made subject to interpretation by the contents of the ST field and indicates an encoded item of telecommunications information only when the ST field is 'busy'. When the ST field requests or acknowledges allocation of the time slot by a TSI, the D/A field respectively identifies the address of the target or requesting TSI.

Distributed switching system having multiple time slot interchanger nodes

A time division switching system having distributed control processors is disclosed. The switching system includes time-slot interchange units having associated subscriber sets and conference circuits and a time-shared space division network for interconnecting the time-slot interchange units. Each of the time-slot interchange units and the time-shared space division network are controlled by separate control processors. In response to called subscriber set identifying information from a calling subscriber set, the control processor associated with the time-shared space division network completes standard communication paths through the time-shared space division network to connect the time-slot interchange units associated with the calling and called subscriber set. Standard communication paths are replaced with conference paths which include a conference circuit, by establishing the conference path, transmitting information on both the standard and conference paths, and selectively releasing the standard path when continuity can be assured on the conference path.

Telecommunication path substitution arrangement

A time division switching system having distributed control processors is disclosed. The switching system includes time-slot interchange units having associated subscriber sets and a time-shared space division network for interconnecting the time-slot interchange units. Each of the time-slot interchange units and the time-shared space division network are controlled by separate control processors. In response to called subscriber set identifying information from a calling subscriber set, the control processor associated with the time-shared space division network completes the communication path through the time-shared space division network to connect the time-slot interchange units associated with the calling and called subscriber sets. The control processors in the time-slot interchange units then determine if communication path continuity is present between them before the subscriber sets are connected to the communication path through the time-slot interchange units. Additionally, arrangements are included for detecting loss of continuity in the communication path.

Continuity verification arrangement

A time division switching system having distributed control processors is disclosed. The distributed processors exchange control messages and cooperate in the completion of talking paths between subscribers. Each control message includes an address portion defining the destination for the control message and is transmitted to a time-shared space division switch on the same time multiplex lines that speech representations are transmitted. Control messages are routed by the time-shared space division switch to a control distribution unit where the address portion is interpreted. When the address portion defines a distributed processor which controls the time-shared space division switch, the control distribution unit transmits the associated control message directly to that processor. Alternatively, when the address portion defines one of the other distributed processors, the control distribution unit transmits the associated control message to the defined processor via the time-shared space division switch. The switching system also includes arrangements for utilizing the control message communication features in the completion of communication paths between subscribers.

Time division switching system control arrangement

A speech recognition system is realized by applying a speech signal to a feature extractor wherein a sequence of predetermined features representing the speech signal are determined, and by comparing the determined features, in an acceptor, to predetermined sequences of features which represent selected words. One attribute of the feature extractor is the ability to represent certain classes of sounds in terms of the position and direction of motion of the movable structures of a human vocal tract model, such as the position and direction of movement of the speaker's tongue body. The tongue body position is derived by determining the formant frequencies in the applied speech signal and by employing the Coker vocal tract model to find the tongue body position which best matches the determined formants.

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Winfield, IL, United States of America

Edward H Hafer