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Reducing Response Time Requirements of Terminals in a Loop Communications Network

IP.com Disclosure Number: IPCOM000082674D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cramer, CE: AUTHOR

Abstract

Described is an improvement in the operation of the loop disclosed in U.S. Patent 3,752,932. According to the mode of operation in the above patent, the central or primary station issues an enable signal which is immediately followed by a continuous stream of 1 bits. The terminals on the loop recognizing the enable signal search for seven continuous 1 bits. Upon detecting this condition if the terminal has data, it changes the seventh received bit to a 0 and starts its message with an address code, control code, data and block checking characters, if desired.

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Reducing Response Time Requirements of Terminals in a Loop Communications Network

Described is an improvement in the operation of the loop disclosed in U.S. Patent 3,752,932. According to the mode of operation in the above patent, the central or primary station issues an enable signal which is immediately followed by a continuous stream of 1 bits. The terminals on the loop recognizing the enable signal search for seven continuous 1 bits. Upon detecting this condition if the terminal has data, it changes the seventh received bit to a 0 and starts its message with an address code, control code, data and block checking characters, if desired.

Terminals on the loop must make a decision on whether or not to respond within six bit times, in order to achieve control of the loop at the appropriate time. In many instances, due to terminal construction, this turnaround capability may not be possible. In order to relieve the terminals of this rapid response criteria, each of the secondary terminals may be configured to seize the link immediately upon recognizing the seventh 1 bit, whether or not the terminal has data to transmit. Thereafter, the terminal transmits one or more fill characters which will not permit subsequent terminals to seize the line, and which will not be interpreted as data by the central or primary station.

While transmitting the fill character(s), the terminal may process the previously received message and either transmit a message in response thereto...