Browse Prior Art Database

Video Line Concentrator

IP.com Disclosure Number: IPCOM000041908D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Massiera, L: AUTHOR [+2]

Abstract

This is a line concentrator for concentrating video terminal signals using TASI (Time Assignment Speech Interpolation)-type techniques over a limited number of transmission lines. N input terminals (e.g., 100) are individually connected to an analog matrix through modems. The N input lines are concentrated over N' (e.g., 16) output lines. Over these N' lines, N1 (e.g., 10) are used for the video data information transmission; N2 (e.g., 4) are used for performing Voice Activity Detection (VAD) operations; and N3 (e.g., 2) are used for transmitting traffic congestion information. Four subroutines, namely, SR1, SR2, SR3 and SR4, are provided for controlling the concentrator operations. Each one of the N2 lines is made to control VAD over N/N2 input lines.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 1

Video Line Concentrator

This is a line concentrator for concentrating video terminal signals using TASI (Time Assignment Speech Interpolation)-type techniques over a limited number of transmission lines. N input terminals (e.g., 100) are individually connected to an analog matrix through modems. The N input lines are concentrated over N' (e.g., 16) output lines. Over these N' lines, N1 (e.g., 10) are used for the video data information transmission; N2 (e.g., 4) are used for performing Voice Activity Detection (VAD) operations; and N3 (e.g., 2) are used for transmitting traffic congestion information. Four subroutines, namely, SR1, SR2, SR3 and SR4, are provided for controlling the concentrator operations. Each one of the N2 lines is made to control VAD over N/N2 input lines. For that purpose, the SR2 subroutine is made to scan a group of N/N2 input lines and perform demodulation and detection operations as well as zero deletion and SDLC (synchronous data link control) decoding. Then SR2 is made to detect whether the scanned line is effectively active. For instance, a continuous carrier detection, i.e., a continuous series of SDLC flags, is considered as denoting inactivity. For each active scanned line, the SR2 subroutine branches to the subroutine SR4 which, in turn, connects the active input line to one of the N1 output lines. In case none of the N1 lines is available, the SR2 branches to the SR3 subroutine. The latter sends congestion information to the consi...