Browse Prior Art Database

Modem With Mixed Multiplexing and Fanout Functions

IP.com Disclosure Number: IPCOM000061497D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Epenoy, G: AUTHOR

Abstract

Data multiplexing in synchronous modems uses multibit per baud encoding to create different independent channels working simultaneously. Data, elastic buffering, channel interface status, channel wrap tests, etc., are microprocessor-controlled. The microprocessor is given access for the different channels via a set of fixed addresses IEA for the first channel, B for the second channel, etc. The data transmission rate allocated to a channel is specified by the CCITT recommendations. The fanout function consists in duplicating the modem interface to allow several attachments of data terminal equipment (DTE) or connected data communication equipment (DCE) to work alternatively in a multipoint configuration.

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Modem With Mixed Multiplexing and Fanout Functions

Data multiplexing in synchronous modems uses multibit per baud encoding to create different independent channels working simultaneously. Data, elastic buffering, channel interface status, channel wrap tests, etc., are microprocessor- controlled. The microprocessor is given access for the different channels via a set of fixed addresses IEA for the first channel, B for the second channel, etc. The data transmission rate allocated to a channel is specified by the CCITT recommendations. The fanout function consists in duplicating the modem interface to allow several attachments of data terminal equipment (DTE) or connected data communication equipment (DCE) to work alternatively in a multipoint configuration. The proposed approach consists in mixing the multiplexing and fanout functions by using an interface port addressing scheme wherein several ports are given the same logical address, in addition to their physical address. This logical address is dynamically allocated by loading a register associated with each physical port. For example, when the multiplex configuration is in "two channel" mode, A port is given logical address A and B port logical address B, each of the A and B ports working at 7200 bps in a modem at 14,400 bps, and ports CDE and F being unused. Then it is possible to allocate logical address A to ports C,D,E and to allocate logical address B to port
F. The data stream dedicated to the A port will...