Comsat Corporation

Jack H Rieser

Spiros S Dimolitsas

Michael Onufry, Jr

Henri G Suyderhoud

Krishnamoorthy Virupaksha

Vaikunth N Gupta

A facsimile communication system including a first communication station for receiving voiceband facsimile signals and for converting the received signals to baseband signals, and for transmitting the baseband signals, and a second communication station for receiving the transmitted baseband signals. The first communication station is able to generate a control code which identifies to the second communication station that the first communication station includes enhanced and/or proprietary capabilities.

Provision of proprietary and enhanced capabilities in Group 3 facsimile

A facsimile communication system including a first processing circuit, connected to receive a facsimile signal from a first facsimile device, for converting the analog voiceband facsimile signal into a digital code signal representing information carried in the analog voiceband signal, and for transmitting the digital code signal; a second processing circuit, connected to receive the transmitted digital code signal from the first processing circuit, for converting the received digital code signal into an analog voiceband facsimile signal; and a second facsimile device, connected to receive the analog voiceband facsimile signal from the second processing circuit. The digital code signal includes a digital code which is repeated in the digital code signal an integral number of times. In another embodiment, the digital code signal contains another binary code which represents the position, within a data field, when information was first detected by the first processing circuit.

Line state transmission system over digital channels for group 3

An apparatus for and a method of permitting the in-band negotiation of enhanced capabilities between two or more facsimile interface units (FIUs) by using FIU capabilities control packets containing a plurality of data cells carrying information of the capability negotiation information is disclosed. In operation, a called station identification signal is transmitted from a remodulating FIU together with a special capabilities packet following the end of a line control packet. The calling FIU may issue a response agreeing to or modifying the compatible enhancements by sending its own special capabilities control packet containing compatibility negotiation information. In another aspect of the present invention, an FIU adds a set of data cells to a line control packet to minimize the possibility of data cell alignment due to degraded channel conditions. In accordance with the present invention, a unique word is selected and transmitted in the set of data cells so as to enhance the system performance and protocol tracking capability of the receiving FIU.

Facsimile interface unit (FIU) enhanced capabilities negotiation

A low-rate encoding/digital speech interpolation (LRE/DSI) system architecture is organized to eliminate the LRE mistracking problem normally associated with DSI-induced speech clipping, to reduce the number of LRE codes required and to provide a mechanism for gradually introducing overload.

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Middletown, MD, United States of America

Jack H Rieser