Abstract: A method for the compression of data applied to a system for the transmission of data in protocol data units between at least one emitter terminal and at least one receiver terminal. Each protocol data unit comprises a header field and a data field. A first sequence of N source protocol data units is associated with a second sequence of M protocol data units to be transmitted, M being smaller or equal to N. The data fields of the protocol data units transmitted comprise data that has been compressed (according to at least one compression algorithm). The data fields are then made up of data contained in the data fields that has been compressed, and also data allowing reconstruction of N source protocol data units.

Abstract: A system of data transmission by packets in which certain data-exchange links use a transmission chain comprising two transmitter/receiver terminals and at least two intermediate units, and in which each packet is associated with the transmission of data belonging to only one link, at least some of the intermediate units including means for the compression and/or decompression, in at least one direction of transmission, of the data elements contained in the data fields of the packets transmitted, according to at least one compression algorithm. The compression and decompression units are allocated selectively to some of the links, to compress the data elements transmitted on at least a portion of the transmission chain. The compression/decompression function is selectively activated in the allocated units for at least one series of consecutive packets of the corresponding link, and is selectively deactivated for the other packets.

Abstract: An advanced network processor or concentrator which uses distributed processing to interface a plurality of subscriber data input lines to a packet network. The concentrator includes removable line terminators boards (ULT) which can be configured to handle a variety of signal characteristics. Each ULT interfaces to a line director unit (LDU). The line director units process and packetize the data. All the LDU's are interfaced to each other over a high speed data bus which is also accessible by a nodal director unit (NDU). Each LDU is programmed by the NDU to recognize and process the data at each subscriber line and instructed by the NDU to down load it's processed data to a selected trunk line director unit (TLDU). The TLDU transmits the data over a trunk line to a packet switching network. The system is modular, expandable and reprogrammable to handle differently typed subscriber inputs as necessary.