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Reception at Character Start

IP.com Disclosure Number: IPCOM000094832D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Harbour, WP: AUTHOR [+3]

Abstract

One significant source of error in a communication system occurs when a receiver begins reception in the middle of a message. In this instance, middle portions of two character codes closely following in time can be interpreted as a single, incorrect code. To effectively eliminate this source of error, a delay is inserted at the receiver between turnon and effective reception of characters.

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Reception at Character Start

One significant source of error in a communication system occurs when a receiver begins reception in the middle of a message. In this instance, middle portions of two character codes closely following in time can be interpreted as a single, incorrect code. To effectively eliminate this source of error, a delay is inserted at the receiver between turnon and effective reception of characters.

Errors generated by reception of incorrect codes are particularly significant in systems of printing terminals which are addressed, and in which receivers, in some addressed status, automatically transmit certain replies. In such a system, a certain character is reserved for addressing, but it can occur in an incorrect code received when reception starts in the middle of a character.

A start bit indistinguishable from one of the two data bits precedes each character and the received bits are stepped to the end of a shift register. A stop bit indistinguishable from the other of the two data bits terminates each character. The shift register is read out in parallel when what appears to be a start bit is moved into the last stage and when what appears to be a stop bit simultaneously appears in the first stage. When the read out signals are not acted upon until the expiration of a few seconds delay, the received signals may be cleared from the shift register a large number of times.

Two factors each contribute to assure that the machine has cleared out...