General Electric Company

Ericsson Ge Mobile Communications Inc.

Ericsson Gmbh

Satish Kappagantula

Charles P Brame

James L Teel, Jr

Eugene Harold Peterson, Iii

Timothy F Cree

Craig F Szczutkowski

Stephen R Downs

Richard Louis Zinser

Wim A Imron

Philip C Gulliford

A dispatcher console for use in a digitally trunked, multisite public service radio system. The dispatcher counsel comprises a personal computer having a co-processor logic board, an audio switching tower, and user I/Os including a customized keyboard, display screen, audio speakers, headset and a transmit foot pedal. The switching tower routes audio communications between the console and multisite switch. The tower is controlled by and connected directly to the co-processor board. The customized keyboard is also connected directly to the co-processor board and has dedicated keys for commonly performed functions. The display screen presents information in a standard format such that the dispatcher knows precisely where to find particular information.

Display console and user interface for multisite RF trunked system

A multisite network switch for a series of RF digital trunked radio transceivers and dispatcher consoles. The switch establishes audio communications between different sites and various dispatcher consoles. The multisite switch has a distributed architecture in which each node of the switch is supported by a microprocessor controlled card. This card has a communications controller that routes messages between the internal switch bus, an outside port and an interface processor that controls the audio slots in the switch. The communications controller receives control messages from the switch bus, but discards redundant slot status messages by checking a slot status bit map stored in a memory unit on the card.

Message bus slot update/idle control in RF trunking multisite switch

A communication link for a dispatcher console to a multisite network of RF digitally trunked radio site transceivers and other dispatcher consoles. The communication link provides the dispatcher console direct access to a wide area RF network. A multisite central switch establishes audio and control communications between the different sites and various dispatcher consoles. The dispatcher consoles have audio and control links to the multisite switch. The multisite switch has a distributed architecture in which a switch node interfaces with the dispatcher console. A control communication protocol provides a standard format for message packets between the multisite switch and dispatcher console.

Communication link between multisite RF trunked network and an

Hybrid subband coding and decoding (using different encloding/decoding algorithms in at least one subband channel) and subband time delay compensation at a point of maximum digital bandwidth compression are effected so as to reduce required DSP on-chip memory requirements. At the same time a special digital signal format is employed so as to provide enhanced data frame synchronization, enhanced cryptographic synchronization and selective signalling ability within a cryptographic digital signal transceiver. The ability to successfully accomplish late entry (or to re-establish synchronization once lost) into an ongoing received message is provided.

Cryptographic digital signal transceiver method and apparatus

Method and apparatus are disclosed for transceiving digital control and cryptographically encoded data signals in a unique format. The format includes frame synchronization, cryptographic synchronization and selective signalling (addressing) information both in a preamble portion to an entire message and recurrently at regular intervals throughout a message of encrypted digital voice signals. This arrangement permits successful late entry and/or synchronization recovery (both frame and cryptographic synchronization recovery) in an addressable selective signalling type of private radio communication system even if such synchronization is never acquired from the preamble (e.g. because of a long radio transmission channel fade or the like) or in the event such synchronization is temporarily lost after the preamble has already occurred.

Growing community of inventors

Lynchburg, VA, United States of America

Satish Kappagantula