Browse Prior Art Database

Very High Speed Communication Controller/Pbx Concentrator

IP.com Disclosure Number: IPCOM000038457D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Baudelot, F: AUTHOR [+2]

Abstract

A very high speed communication controller/PBX concentrator is provided. Time Division Multiplexing (TDM) without buffering of the data stream with the digitized voice on a very high speed link is achieved. A free-running clock to Tie-Line Adapters (TLAs) and a stuttering clock to the Link Interface Circuits (LICs) of the communication controller is achieved. Earth and Mark (E and M) for signalling are coded and checked from TDM unit to TDM unit with a retry procedure to take into account the bit error rate on the digitized link. The device uses a 2.048 Mbps data link. The communication controller handles 1.5 Mbps; the remaining 512 Kbps can be used to transmit the digitized voice. PBX-to-PBX connection on this bandwidth is possible by multiplexing the digitized voice into the Communication Controller data stream.

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Very High Speed Communication Controller/Pbx Concentrator

A very high speed communication controller/PBX concentrator is provided. Time Division Multiplexing (TDM) without buffering of the data stream with the digitized voice on a very high speed link is achieved. A free-running clock to Tie-Line Adapters (TLAs) and a stuttering clock to the Link Interface Circuits (LICs) of the communication controller is achieved. Earth and Mark (E and M) for signalling are coded and checked from TDM unit to TDM unit with a retry procedure to take into account the bit error rate on the digitized link. The device uses a 2.048 Mbps data link. The communication controller handles 1.5 Mbps; the remaining 512 Kbps can be used to transmit the digitized voice. PBX-to-PBX connection on this bandwidth is possible by multiplexing the digitized voice into the Communication Controller data stream. A multiplexing without buffering normally implies a stuttering clock for the data to permit the synchro slot insertion (frame + superframe). But a multiplexing without buffering for 64 Kbps PCM voice requires a 64 Kbps free-running clock. The TDM must provide a 64 Kbps free running clock to the TLA and a stuttering clock (256 Kbps max) to the LICs.

E/M coding allows a protocol which provides checking and retries for signaling. The frame and the super frame are described in the figure. The abbreviations are defined below: Dn = data bit from LIC number n

Vn = Voice PCM bit from TL number n

S'yn = synchro pattern bit number n of the slot S'o

Syn = synchro pattern bit number n of the slot So

Enm = bit number m of the "control word and E/M coding"

from TL number n (m = 1 to C(hexa), n = 1 to 8)

S = standard slot

So = slot with superframe synchro pattern

S'O = SLOT WITH FRAME SYNCHRO PATTERN A "control word and E/M coding" occurs every millisecond for a defined tie-line. This 12-bit word is transmitted o...