International Business Machines Corporation

Claude J Gergaud

Claude R Galand

Pierre Secondo

Paul Raymond Callens

Andre G Tracol

Etienne Grimanelli

Philippe Noailly

A method of transmitting digitized voice signals as packets of bits in a digital transmission network to which a plurality of terminals acting as sources of voice signals are attached. The method includes, at the transmitting end and for each source, the steps of: a dividing the signal into successive, digitally-coded segments; performing a so-called source activity detection; and assembling the bits resulting from the coding operation into packets, each packet being provided with a header containing, in particular, a parity bit whose logic value is modified whenever an inactivity or long pause is detected. At the receiving end, detection of a change in the value of said parity bit causes the delivery of a packet of bits to the decoder/synthesizer to be delayed by a given time interval called retention delay.

Method and system for transmitting digitized voice signals as packets of

Described is a decentralized data transmission system and a method of operating the system. A relatively high speed transmission medium connects a number of relatively lower speed terminals in a loop or similar configuration. A central or monitoring station is connected in the transmission medium which includes a memory table containing the listing of the station addresses connected to the transmission loop. The monitoring station operates as a control station for transmitting the address of a first station to be enabled to transmit a message. The addressed station recognizes its address and responds either with a message destined for another station or with a signal that no message is to be sent. At the end of a message, an enabled station sends a special character to notify the monitoring station that the next station in the memory table can be addressed to grant usage of the transmission medium.

Decentralized data transmission system

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Cagnes sur Mer, France

Claude J Gergaud