British Telecommunications Public Limited Company

British Telecommunications Corporation

John W Ballance

David W Faulkner

Donald E Clarke

Michael A Hale

Richard P Scott

Michael T Hewitt

Steven J Edwards

Monitoring system

TDMA communications network of transmitting information between a

In a network including an exchange having a masterclock and a number of subscriber stations connected to the exchange, the exchange includes a delay line which receives incoming data. Samples are taken from different taps of the delay line and the tap carrying data in phase with the masterclock is identified and used to output data. In a preferred example, the network is an optical network carrying data cells.

Network clock synchronization

Scrambling in digital communications network using a scrambled

Optical communications network

TDMA/TDM interfacing

The node of a point to multipoint data telecommunications system needs a receive clock to regenerate the data. The conventional method of regenerating the clock from received signals is difficult because there are gaps when no outstation is active. The invention reduces these problems by synchronizing the receive clock with the master send clock when there is no reception.

Multipoint data communications

In a time division multi-access communications system each burst in each slot commences with a preamble and the clocks used to control the sequence of operations are synchronized by means of these preambles. In particular the outstations control their transmissions to the node by timing pre-set delays from the receipt of the preamble. In a preferred embodiment the pre-set delays are adjusted by signals from the node so that bursts arrive at the node in correct sequence.

Communications network having a single node and a plurality of

Growing community of inventors

Woodbridge, United Kingdom

John W Ballance