Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness and reliability. The mobile radio transceivers transmit channel requests on the control channel at 9600 bps. The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Message and transmission trunking capabilities are both present so as to maximize working channel usage without compromising channel access for high priority communications. Radios select between message and transmission trunking based on over-the-air signaling. During transmission trunking, called and calling receivers return to the control channel after each transmission (and called transceivers may be inhibited from transmitting) but grant higher priority to calls from the other transceivers being communicated with to ensure continuity over an entire conversation.

Abstract: A RF site link for communicating between a centralized switching system and a plurality of mobile communications RF base stations is disclosed. The RF site link includes a plurality of RF link devices connected to centralized switching equipment. The RF link devices transmit signals to and receive signals from the remote base stations over the same working channels that the base stations use to communicate with the mobile or portable radios within each of the base stations' areas of operation. A RF control link is provided to control the assignment of the working channels between the centralized switching equipment and each of the base stations within the system.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A gateway between a non-trunked ("conventional") RF communication system and digitally trunked RD communication system maps between trunked group IDs and non-trunked subaudible signalling tone frequencies. An interface between the two systems thus forms a "super group" including both trunked and non-trunked radios that can automatically communicate together. The gateway permits a customer to continue to use non-trunked components, and to cost-effectively integrate such components into a state-of-the-art trunked radio communications system.

Abstract: A single channel autonomous trunking ("SCAT") RF repeater transmits and receives on a single duplex RF channel. The repeater operates alternately in a control channel mode and in an assigned channel mode. Digital control channel signalling results in temporary assignment of the single channel for assigned channel signalling (e.g., mobile generated messages). A holdover time period following reversion of the channel to control channel signalling minimizes collisions and permits priority to be given to emergency communications. Low speed data subaudible digital signalling may be used to provide late entry capabilities.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A site architecture for a trunked radio frequency communications system provides better fault tolerance capabilities than are available from architectures including redundant hardware. During normal system operations, a primary site controller performs most or all system control functions while signal processing functions are performed in a distributed manner by trunking cards associated with individual repeater channel receivers and transmitters. In the event the site controller fails, the trunking cards also begin performing trunking and other control functions. The trunking cards cease attempting to communicate with the failed site controller, and begin communicating directly with one another via a high speed backup serial link.

Abstract: A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages.

Abstract: A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages.

Abstract: A site architecture for a trunked radio frequency communications system provides better fault tolerance capabilities than are available from architectures including redundant hardware. During normal system operations, a primary site controller performs most or all system control functions while signal processing functions are performed in a distributed manner by trunking cards associated with individual repeater channel receivers and transmitters. In the event the site controller fails, the trunking cards also begin performing trunking and other control functions. The trunking cards cease attempting to communicate with the failed site controller, and begin communicating directly with one another via a high speed backup serial link.

Abstract: A digital voter system for a multi-site public service trunking (PST) digitally trunked RF communications system operates on the principle that it is highly likely that messages received during a system redundancy removal period are redundant messages. For a given RF channel, digital receiver is associated with each of multiple sites and receives digital messages reported to it by its associated sites. The multiple digital receivers are connected to a digital selector via a service request line (FSL) and a serial data line (BSL). Digital receivers which have messages to transfer to the digital selector attempt to seize the service request line and, if they successfully seize it, maintain the line in its seized state for the redundancy removal period. Digital receivers which have messages but discover the service request line is already seized simply discard their messages.

Abstract: A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignement message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digital voter system for a multiple site digitally trunked RF communications system includes an improved voting arrangement which tests for actual redundancy before removing redundant messages--thereby decreasing retransmission traffic in simulcast and other large coverage area RF trunking systems. Status messages indicating ongoing call reception are generated periodically by each receiver site which receives a given call. The status messages are received by a digital voter, which in a clear voice mode is used to determine (in responses to the status messages) whether an analog voter should maintain a clear voice call.

Abstract: A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digital radio RF signalling protocol communicates either digitized voice or digital data signals and indicates the type of information being communicated to the receiver. Multiple repeats of control signals are provided for face protection and to ensure correct receipt even under adverse communications channel conditions. When the destination transceiver receives a transmitted digital data burst from the transmitter, the destination transceiver transmits a responsive acknowledge message and may specify in the acknowledge message which portions of the received message were received incorrectly and should be retransmitted by the originating transceiver. The originating transceiver determines the contents of subsequently-transmitted data burst based upon the information it receives from the destination transceiver by way of the acknowledge message. As deleterious phenomena (e.g.

Abstract: A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages.

Abstract: Cooperation between two repeater transceivers of a radio trunking system causes a mobile radio transceiver to join or rejoin ongoing communications. To join ongoing communications, a radio transceiver attempts to acquire a free repeater communications channel by transmitting call signalling identifying a group of transceivers to be contacted. If the group to be contacted is already communicating on another repeater communications channel, the calling radio transceiver is forced to leave the communications channel it is trying to acquire and to begin scanning communications channels in search of call signalling identifying it. Meanwhile, the repeater permitting the ongoing communication interrupts the ongoing communications briefly and transmits the call signalling identifying the group of transceivers to be joined (including the radio transceiver which is to join the ongoing communications).