Abstract: Communication units are provided access to a communication system (100) in the following manner. A base station (202) receives, from a requesting communication unit, a request, via a shared inbound communication resource (209), for an available message path (207). When a dual-mode outbound communication resource is operating in a control mode (205), the message path (207), having a first inbound communication resource (204) and the dual-mode outbound communication resource operating in a partial control mode (206), is assigned to the requesting communication unit. Thus, the shared inbound communication resource is consistently available, providing access to the communication system.

Abstract: Data to be transmitted from an information source (301) associated with a local/wide area network (303) is formatted into a plurality of data packets. Each data packet includes a first target destination identifier that uniquely identifies a target destination (323) within an RF communication system (306). A network interfacer (305) establishes connectivity between the local/wide area network and a controller (307) associated with the RF communication system. Based on the first target destination identifier, the controller determines a second target destination identifier corresponding to the target destination. A circuit-switched channel is established to the target destination using the second target destination identifier. The data packets are then transmitted via the circuit-switched channel to the target destination without either the first or second target destination identifiers being transmitted therewith.

Abstract: A monitoring computer monitors the communications occurring within at least one communication system for at least one unique processing device identification code associated with a processing device. Upon detecting the at least one device identification code, the monitoring computer compares the type of application in use by the processing device with known software parameters (including the allowable types of applications and their serial numbers) for the processing device. When the type of application in use by the processing device does not substantially match the known software parameters for the processing device, the processing device is identified as using an unauthorized and/or duplicated software application.

Abstract: A monitoring computer (115) monitors a communication resource within a wireless communication system for transmissions by communication units. Upon detecting transmissions, which contains a communication unit personality code, the monitoring computer compares transmission time and location information, stored in a database (117), for the communication unit to determine if multiple communication units are using the same communication unit personality code. If multiple communication units are detected, the monitoring computer reprograms at least a portion of service access information of the communication units. In this manner, discrepancies in communication unit programming may be detected and corrected.

Abstract: Within a transmitter (101), a quantity of data (201) to be transmitted is parsed into variable length, uniquely identified messages (202), which are in turn parsed into fixed-length, uniquely identified blocks (207-211). Messages are buffered and then transmitted to a receiver (103). Upon reception of a message-received communication by the transmitter (101) corresponding to a particular buffered message, that particular message is unbuffered. Upon reception of a message-partially-received communication by the transmitter (101) corresponding to a particular buffered message, those blocks corresponding to portions of the particular buffered message that were not adequately received (703) are retransmitted.

Abstract: While participating in a group call on a first wireless communication resource 114, senior members 104-107 of a communication group 108 can initiate a semi-private call. A central controller 110 allocates a second wireless communication resource 115 for the semi-private call. Furthermore, executive members 106-107 can initiate an executive call to be established on a third wireless communication resource 116. Executive members can participate in the executive call, the semi-private call, and the group call, whereas senior members can participate in the semi-private call and the group call. Junior members 101-103, normally allowed to participate only in the group call, can be selected by senior members to temporarily participate in the group call and the semi-private call.

Abstract: A first communication unit (101) transmits, to a central controller (105), a request for a group call. The central controller allocates a first inbound (11), a second inbound (12), and an outbound (O.sub.1) wireless communication resource for use in the group call. At the central controller, primary voice signals from the first communication unit, received via the first inbound wireless communication resource, are summed (109) with interrupt voice signals from a second communication unit (102), received via the second inbound wireless communication resource, to produce summed voice signals. The summed voice signals and a busy signal (108) are transmitted via the outbound wireless communication resource, thereby allowing the second communication unit to interrupt the group call. Additionally, the central controller can allocate a third inbound communication resource (13) for use with priority interrupt voice signals which can also be summed with the primary and interrupt voice signals.

Abstract: Within a communication device which utilizes digital encryption, volatile and non-volatile memory devices are used for the storage of encryption keys in unencrypted and encrypted form, respectively. A power sensing circuit, in conjunction with tamper detection circuitry, is used to help ensure the active erasure of keys from the volatile memory in the event of a non-secure operating condition.

Abstract: A method of manufacturing is employed to produce a size-reduced frequency control device (300), according to the present invention. A temperature compensation circuit (304) and an unsealed piezoelectric element (302) are disposed on a substrate (306) such that the compensation circuit and the unsealed piezoelectric element are electrically connected. A hermetic seal (318) is established between a lid (308) and the substrate such that the unsealed piezoelectric element and at least a temperature sensitive portion of the temperature compensation circuit occupy a sealed environment (320). In this manner, dimensions (322, 324) of the frequency control device are reduced.

Abstract: A surface-mountable crystal resonator (100) is provided in the following manner. A first predetermined electrode pattern (105) and a second predetermined electrode pattern (201) are formed on a first major surface (104) and a second major surface (200), respectively, of a piezoelectric crystal substrate (101). Additionally, a first predetermined attachment electrode pattern (106), electrically coupled to the second predetermined attachment electrode pattern, and a second predetermined attachment electrode pattern (202), electrically coupled to the first predetermined attachment electrode pattern, are formed on a first attachment area (102) and a second attachment area (103), respectively. The first and second attachment areas include extensions (107) that, when mounted, allow a conductive adhesive (301), placed on a mounting substrate (300), to flow and establish electrical connections with the first and second predetermined attachment electrode patterns.

Abstract: A resource allocator (108) receives, from a first communication unit, a request to establish secure communications with at least a second communication unit. A key identifier is retrieved by the resource allocator and transmitted to at least the second communication unit. Based upon the transmitted key identifier, the second communication unit retrieves an identified encryption key and, at least when the identified encryption key is corrupt, transmits a corrupt key indication to the resource allocator. In response, the resource allocator can assign a default key identifier for use in the secure communication. In this manner, missed communications due to encryption key failures are reduced.

Abstract: In a wireless communication system, unauthorized access may be prevented upon detecting the particular type of identification code. When the identification code is of a default enabled type, the central controller (101) transmits a default enabled message to the system manager (110). The system manager interprets this message and provides a response to the central controller (101). The response may indicate that this particular identification code should be activated or deactivated.

Abstract: A voice packet, containing coded voice information for a communication talkgroup that is currently being monitored, is received and stored in a buffer (200-202) dedicated to the communication talkgroup. When a decoder (203-205) is available, the voice packet is decoded and the resulting decoded voice information is combined with other decoded voice information, pertaining to other monitored communication talkgroups, such that the combined decoded voice information can be rendered audible.

Abstract: In a communication system, an operator station provides dispatch services to communication groups and multi-communication groups. When a request is received by the operator station to provide a particular dispatch service, which requires at least one multi-communication group to be modified, a temporary multi-communication group is created based on the request and predetermined communication system limitations. After the particular dispatch service has been performed for the temporary multi-communication group, the temporary multi-communication group is discarded, returning the temporary multi-communication group to the at least one multi-communication group.

Abstract: In a simulcast communication system (100), a communication unit (110-115) may request enhanced coverage area services by transmitting a request for enhanced signal quality to a central simulcast controller (101). Upon receipt, the central simulcast controller (101) identifies, based on information pertaining to the location of the communication unit, a set of transmitters (102-109) to enhance coverage in the area of the communication unit. The central simulcast controller determines enhanced coverage area delays for each of the transmitters and adjusts the respective delays of each transmitter such that transmitted signal quality is enhanced at the location of the communication unit.

Abstract: In a secure trunking communication system, limited secure service is provided during periods of limited service or failsoft operations using the following method. When the limited service or failsoft condition is detected, a limited secure service message or a failsoft service message, respectively, is transmitted to those system components utilizing encryption keys, including console interface units (CIU) (106-107) and communication units (111-113). Upon reception of the limited secure service message, the communication units load at least one limited service key. Simultaneously, the console interface units also load the at least one limited service key. Upon reception of the failsoft service message, the console interface units load at least one failsoft key. Simultaneously, the communication units also load the at least one failsoft key. The communication units and the CIUs use the limited service keys or the failsoft keys until normal operation is restored.

Abstract: A database unit monitors the communications occurring within at least one communication system for hardware identification codes of communication or broadcast units. Upon detecting the hardware identification code, the database unit compares the one received with a stored hardware identification code for the unit. When the stored hardware code does not match the one received, the database unit indicates that the unit has undergone an unauthorized modification.