Browse Prior Art Database

DATA Multiplexing in Modems

IP.com Disclosure Number: IPCOM000047608D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Epenoy, G: AUTHOR [+3]

Abstract

In a modern data communication link, diagnostic data have to be inserted within the flow of pure data without disrupting normal traffic. At each end of the communication link, data operations involve taking low speed inputs from the active terminal (DTE) ports and combining them into one high speed data stream for a companion modem attached to the Data MPX. In the opposite direction, a high speed data stream delivered by the modem has to be converted into a series of low speed outputs to the active DTE ports. Diagnostic requests and answers may be inserted as if they were pure data. As far as diagnostic is concerned, any of the modems within the network may be able to detect a specific bit pattern announcing a diagnostic request, then decode the request and monitor, the performance of the diagnostic command.

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DATA Multiplexing in Modems

In a modern data communication link, diagnostic data have to be inserted within the flow of pure data without disrupting normal traffic. At each end of the communication link, data operations involve taking low speed inputs from the active terminal (DTE) ports and combining them into one high speed data stream for a companion modem attached to the Data MPX. In the opposite direction, a high speed data stream delivered by the modem has to be converted into a series of low speed outputs to the active DTE ports. Diagnostic requests and answers may be inserted as if they were pure data. As far as diagnostic is concerned, any of the modems within the network may be able to detect a specific bit pattern announcing a diagnostic request, then decode the request and monitor, the performance of the diagnostic command. The response to these commands may convey a modem status or the quality of the signal received over the communication facility. Test requests and test responses utilize the same data path and protocols that are used for data transmission. Some diagnostics may even be carried out for one or more than one port without disrupting data operations on other active ports. The figure shows the pure data and diagnostic data flow for one port (Port A). The bits provided by Port A are simultaneously fed into an elastic buffer and into the DIAG Detect. The same figure applies for all other active parts. The data bits from active elastic buffer...