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Transmission Synchronizing Method

IP.com Disclosure Number: IPCOM000090457D
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Donnan, RA: AUTHOR

Abstract

This synchronizing method establishes start of message SOM and end of message EOM signals in a continuous bit-by-bit transmission together with data transparency by preventing such SOM or EOM signals in the body of the message. The method provides for such functions with a minimum of nonsignificant bit signals.

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Transmission Synchronizing Method

This synchronizing method establishes start of message SOM and end of message EOM signals in a continuous bit-by-bit transmission together with data transparency by preventing such SOM or EOM signals in the body of the message. The method provides for such functions with a minimum of nonsignificant bit signals.

An SOM signal comprises eight or more 1 bits followed by a 0 bit, --- 1111 1111 0. An EOM signal is eight 1 bits followed by a 0 bit, DDD 1111 11110 ---, the D representing a data bit. The bit sequence between the EOM and SOM signals does not represent data and can be any pattern so long as it does not contain the SOM signal, i.e., a full string of 1's is satisfactory and can be used as part of the start signal.

To prevent improper data reception, it is necessary to prevent the occurrence of the SOM or EOM signal in the data. This is accomplished by preventing any group of eight l''s from being transmitted. A counter counts the number of 1's in a sequence, i.e., it is reset on each transmitted 0, and automatically causes transmission of a 0 each time it counts to seven. In the receiver, the reverse operation takes place with a counter counting the consecutive 1's received. If the counter counts to seven, the next bit is sampled and deleted if it is a 0 bit. If the bit is 1, the grouping is an SOM or EOM signal group and the receiver is alerted for the receipt of the following 0 bit to indicate the change of transmission st...