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Delay Counting Rates in a Communications Multiplexor

IP.com Disclosure Number: IPCOM000075643D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lee, TL: AUTHOR [+3]

Abstract

In a communications multiplexor, hardware controlled timing operations are initiated by special characters in the transmit data stream. These special hardware codes are capable of specifying that a marking or spacing signal be presented to the communication line, or that the line turn around from transmit to receive and wait for input data for a controllable time interval.

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Delay Counting Rates in a Communications Multiplexor

In a communications multiplexor, hardware controlled timing operations are initiated by special characters in the transmit data stream. These special hardware codes are capable of specifying that a marking or spacing signal be presented to the communication line, or that the line turn around from transmit to receive and wait for input data for a controllable time interval.

The timing operations are initiated by the insertion by the programmer of a special character in the transmit data stream. This is accomplished by a control code that specifies special action to be taken (such as a timeout) followed by an 8-bit byte. The 8-bit byte functions as a counter specifying the duration of the special action. Some are very short whereas others are very long. The same counter is used in either case by breaking the counter into a 6-bit counting field and a 2-bit counting rate control field. The 2-bit field selects one of a number of oscillators which is then used to step the 6-bit field at the rate selected.

This is more fully described in IBM System Reference Library Manual "IBM 2969 Programmable Terminal Interchange Model 1, RPQ 88117: Special Feature Description", Order Number CL22-6940-0, copies of which may be obtained from any IBM Branch Office or by writing IBM Product Publication, Department B98, P.
0. Box 390, Poughkeepsie, New York, 12602.

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