Plessey Overseas Limited

Sprint International Communications Corporation

John A Stockdale

John Hewinson

Anthony J Frankish

Ian B Stewart

A technique for interconnecting line processing units (LPUs) of a packet switch and/or data concentrator system in which, instead of using a standard bus system, each LPU has a number of duplex point to point serial links that are connected in either a random or structured manner to provide a network of routes between the LPUs. Information is then transferred between source and destination LPUs as short packets. When the system is expanded by adding more LPUs, the network of serial point to point links expands to provide more routes and, hence, greater bandwidth to handle the increased information flow. Failure of a link in the network is not catastrophic as there are a number of different routes to any LPU and the system only degrades systematically in the event of link failures.

Data packet switching

The invention relates to an adaptive cancellation bridge circuit (ACB) for use in a single medium full duplex line termination equipment such as modems where signals are transmitted and received simultaneously along a pair of wires, the transmit and receive signal being separated in frequency. The bridge comprises a bridge network including transconductance cells (TC1, TC2 and TC3), to provide resistive, capacitive, and inductive components and these cells are electronically controlled by a current control device CC driven from a received signal (RXS) inphase and quadrature components to adjust the bridge network so that it becomes balanced and cancels a transmit signal (TXB) completely.

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Poole, United Kingdom

John A Stockdale