International Business Machines Corporation

Robert P Barner

Joseph M Bensadon

Harold G Markey

Jacques A Besseyre

Jan G Oblonsky

John A deVeer

Anne M Gulick

William M Durham

Synchronization can be acquired between a transmitting node and a receiving node on a time division multiple access communication link without the necessity for additional data bits in the data stream, by correlating the number of errors detected in any interval as revealed by the forward error correction field. Both synchronization bits and stuffing bits can be located without using any external frame timing information. Substantial bandwidth savings is achieved by the technique, which can be applied for arbitrary combinations of the number of input ports, the number of data bits per group, and the number of parity bits generated per group.

Medium speed multiples data

A self-switched in-band signaling communication apparatus is disclosed which enables the switching of the signaling mode to the data mode on a single transmission line between a data terminal equipment or data communication equipment and the data port of a satellite communications controller, and the opposite switching from the data mode to the signaling mode under a single control bit. Signaling to and from the data port of the satellite communications controller is carried out using conventional dialing pulses at a signaling rate which is independent of the line data rate. The apparatus provides for the multipoint communication between a plurality of data terminal equipments using a unique multipoint turn-around process which provides a mobile bandwidth capability for the communications system.

Self-switched data port in-band signaling protocol

A data transmission system which includes stations connected in a closed loop configuration with interface capabilities at each station to connect to an external data processor. Through this configuration simultaneous transmission of data among processors connected to stations on the loop can be carried out by transmission of data around the loop between particular stations. Data is transmitted from a first processor to its individual station connected to the loop. This first station formats the data received from the first processor into frames of multi-bit configuration which are transmitted around the loop to a second station which is connected to a second processor. Data received by the second station is stored and transmitted to the second processor. During the time that this transmission from the first processor to the second processor is being carried out a transmission between other processors connected to stations on the loop can also be carried out. Each station on the loop receives all frames being serially transmitted around the loop and after examination of the address section of the frame will keep frames designated for that particular station and will pass on those frames addressed to other stations on the loop. Each of the stations connected in the loop is an identical unit including a clock generator and synchronizer with no master station being designated for control functions, therefore, no control lines other than a clock timing line are included in the loop. A bypass function selects an alternate path around a station on the loop to permit faulty stations to temporarily be disconnected from the loop bus. Each station has a purging capability which permits frames which have parity errors or illegitimate addresses to be removed from the loop.

Loop configured data transmission system

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Rockville, MD, United States of America

Robert P Barner