Abstract: A system for channel assignment in a trunked transmission communication system including a plurality of subscribers. A plurality of subscribers is provided home channel assignment to reduce collisions. A home channel alias is provided for home channel coverage where a designated home channel is unavailable. A system for call grouping is provided to avoid talk group splitting. A first check is used to determine if other channels are conducting communications with identical home and talk group information. A second check is available after a temporary channel assignment. In one system both the home channel aliasing and call grouping are performed.

Abstract: A trunked radio repeater communication system capable of use in a networked system includes a plurality of distributive switches and a unique signaling protocol and a switching protocol for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities. The trunked radio repeater system including a protocol supporting communications for repeaters and/or subscribers conducting communications using existing protocols, such as the Logic Trunked Radio (LTR) protocol and supporting additional special functions.

Abstract: A trunked radio repeater communication system capable of use in a networked system includes a plurality of distributive switches and a unique signaling protocol and a switching protocol for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities. The trunked radio repeater system including a protocol supporting communications for repeaters and/or subscribers conducting communications using existing protocols, such as the Logic Trunked Radio (LTR) protocol and supporting additional special functions.

Abstract: The present link delay calculation system using a common reference signal and a pulsed or gated tone signal to determine the link delay. The system using a discrete-time Fourier transform to measure phase information and obtain the link delay time. One such system employing a global positioning satellite signal to synchronize signal generation at a control site and demodulation at a remote site.

Abstract: A battery charger is disclosed including a main housing which receives an adapter therein. The adapter receives batteries or other devices to be charged therein. The adapter has alignment projections and multiple levels therein for accommodating many different sizes of devices or batteries to be charged. In addition, the adapter is modular in that it can be modified yet still be received by the main housing for receiving additional devices of different sizes. The adapter seats with the main housing, and has integral attachment members for engaging a base plate thereto. Ventilation apertures are also provided within the main housing, the adapter, and the base plate for allowing sufficient heat dissipation during the charging process.

Abstract: A transmit control system using in-band tones for activating and deactivating one or more remote sites. The transmit control system detecting energy in two or more spectral regions to determine if the signal received is a harmonic signal or a signalling tone to prevent accidental deactivation of the transmitter system. In one application, a modified Goertzel algorithm is employed by a digital signal processor to provide tone detection and a two stage detection provides controlled switching in noisy environments.