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 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: 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 bandwidth management system for a remote repeater network for modifying a first signal to create a second signal within the bandwidth of a communications link, transferring the second signal across the communications link, and reconstructing the first signal at the remote end of the communications link. The bandwidth management system featuring several mixing modes for performing the signal conversion and reconstruction. The system offering a calibration feature to correct for phase distortions introduced in reconstruction of the original signal. The calibration feature incorporating signals from a global positioning satellite system for reconstruction.

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.

Abstract: A method and apparatus for providing priority access for users in a transmission trunked communication system, including a plurality of distributive radio network terminal (RNT) switches and a unique signaling protocol and a switching protocol especially adapted for communication of control signals in the subaudio band for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities.

Abstract: A packet radio communications system having a protocol which provides for nonstandard communications. The protocol providing a standard format indicator to indicate whether a received packet is in a standard or nonstandard format. If the standard format indicator signals a standard packet format, then all transceivers understand the standard information contained in the packet. Transceivers which do not understand the nonstandard format will ignore the nonstandard packet and discard it. The nonstandard format contains a format type code which is decoded along with the standard format indicator to distinguish one manufacturer's nonstandard packet format from another manufacturer's nonstandard packet format. The nonstandard protocol is expanded to manage multiple block packetized transmissions. A Message Continuance (MC) field is incorporated into the header information of the packet to signal the beginning, middle, and end of a multi-block transmission.

Abstract: A battery charger designed for use with a portable battery powered device. The battery charger has a housing and two battery charger ports defined therein, each of the battery charger ports have a first open end at the surface of the housing and a second closed end. The battery charger ports include at least two sets of spaced apart battery engaging electrodes disposed therein. The second closed end of the first charging port has a stepped configuration that defines a first step adapted to receive and hold a first selected battery in electrical contact with a first set of electrodes and a second step adapted to receive and hold a second selected battery in electrical contact with a second set of electrodes.

Abstract: An electronic communication device such as a portable radiotelephone includes a housing and a keypad cover mounted on the housing to rotate about a pivot axis. A hinge connects the keypad cover to the housing and includes a pair of hinge pins extending along the pivot axis between the cover and the housing. The cover includes at least one aperture aligned with the hinge pins, the apertures allowing access to the hinge pins from outside the device to facilitate removal of the keypad cover from the housing. Additionally, the hinge pins include grooved end portions that cooperate with protrusions on the cover to snap the keypad cover toward its open and closed positions.

Abstract: A land mobile transmission trunked communication system is provided with a unique switching protocol arrangement among repeaters that are networked to one or more external communication networks. The land mobile transmission trunked communication system includes a plurality of transceivers for transmitting and receiving transmission trunked radio communications over one or more radio channels. The transceivers communicate with a selected one of a plurality of repeaters to establish transmission trunked radio communications on a preassigned radio channel. The unique switching protocol arangement includes a switch that is operably connected to each repeater and selectively communicates information signals between a repeater and an external communication network. A bus system is operably connected to each repeater and to the switch for communicating control signals among all of the repeaters and the switch.

Abstract: A portable radiotelephone includes a chassis and antenna connector with an impedance of less than 200 ohms, the antenna connector supporting an extendable antenna that is movable back and forth between extended and retracted positions relative to the chassis. The antenna connector also can support a fixed antenna or a connection to external equipment. A universal radiotelephone housing includes a single external connector port for selectively providing electrical connection to both an extendable antenna and external test equipment, precluding the need for separate test and extendable antenna ports. The single external connector port includes an aperture allowing the extendable antenna to pass therethrough.

Abstract: A method and apparatus for distributively interconnecting a plurality of land mobile trunked transmission communication systems into a wide area network includes a plurality of distributive radio network terminal (RNT) switch and a unique signaling protocol and a switching protocol especially adapted for communication of control signals in the subaudio band for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities.

Abstract: An optoelectronic active circuit element is created by the combination of a light source, an optical control filter and a photocell intimately coupled together. The light source has at least one light emitting surface emitting light energy of a specified frequency bandwidth and the photocell has at least one light absorbing surface for receiving the emitted light energy. The optical control filter includes a photorefractive material responsive to an input signal. The optical control filter may also include a polarization filter. The optoelectronic active circuit element modulates the amplitude, frequency or both of the emitted light energy in response to the input signal to produce a characteristic function of the output of the device that is similar to that of a traditional active circuit element, as well as many variations on that function.

Abstract: A land mobile transmission trunked communication system is provided with an enhanced control signal protocol. The land mobile transmission trunked communication system includes a plurality of transceivers for transmitting and receiving transmission trunked radio communications over one or more radio channels. The transmission trunked radio communications comprises an information signal having either voice information, data information, or both, and a control signal. The transceivers communicate with a selected one of a plurality of repeaters to establish transmission trunked radio communications on one of the preassigned set of the radio channels between the repeater and one or more transceivers. The enhanced signaling protocol and switching protocol are especially adapted for communicating control signals in the subaudio band to interconnect a plurality of transmission trunked communication systems into a wide area network.

Abstract: An optoelectronic active circuit element is created by the combination of a light source, an optical control filter and a photocell intimately coupled together. The light source has at least one light emitting surface emitting light energy of a specified frequency bandwidth and the photocell has at least one light absorbing surface for receiving the emitted light energy. The optical control filter includes a photorefractive material responsive to an input signal. The optical control filter may also include a polarization filter. The optoelectronic active circuit element modulates the amplitude, frequency or both of the emitted light energy in response to the input signal to produce a characteristic function of the output of the device that is similar to that of a traditional active circuit element, as well as many variations on that function.

Abstract: A long-life, electrical energy source having an adjustable output is comprised of a light emitting phosphor activated by a radioisotope and coupled to a plurality of photovoltalic cells that have their outputs electrically connected together. The output power of the electrical energy source is effectively regulated by selectively changing the connections of the outputs of the photovoltaic cells in response to the progression of time.