Abstract: A method and apparatus for controlling data transmissions from a first communications unit (202) to a second communications unit (210). Data transmissions received from the first communications unit (202) at the second communications unit (210) are processed to determine a power level of the data transmission. In response to a determination that the power level is not within a desired range or operating window (400), an adjustment value indicating the amount of change needed in the power level of the data transmission from the first communications unit (202) to fall within the desired range or operating window (400) is determined. This adjustment value is sent to the first communications unit (202). In response to receiving an adjustment value from the second communications unit (210), the first communications unit (202) adjusts the power level of its data transmissions.

Abstract: An apparatus and method for recovery of symbol timing for asynchronous data transmission utilizes an RF downconverter (11), an A/D converter (12), and a digital signal processor (14). The digital signal processor (14) includes an error detection block (130), a timing correction block (135), a counter (140), a programmable capture register (145), a clock (150) to produce clock signals, and preferrably a differential detector (155). The error detection block (130) provides information, an error parameter, concerning phase and frequency variances between the clock signal and a transmitted signal. The timing correction block (135) utilizes the error parameter to determine an updated, programmable value stored in the programmable capture register (145).

Abstract: A method for detecting fraudulent use of a communication system (10) includes the steps of determining a system parameter associated with a subscriber unit (32). The system then compares the system parameter to a previous system parameter for the subscriber unit (32). An alarm is set when the system parameter differs more than a predetermined amount from the previous system parameter.

Abstract: A control unit (102) efficiently decodes burst signal transmissions in a TDMA-based telecommunication system (100) by decimating down the number of samples requiring processing during symbol detection. The control unit (102) includes a sampling receiver (304) that inputs burst signals from cable access units, converts them to a pair of baseband quadrature signals, I and Q. The sampling receiver (304) also includes an A/D converter (314) that samples the I and Q signals at preferably four times the symbol rate. A digital signal processor circuit (306) produces a timing error signal for substantially all of the samples. The digital processor circuit (306) also accumulates a timing error sum for each of the four samples. The processor circuit (306) selects the optimum sample as the sample between the samples having the largest positive and negative error sums. The processor circuit (306) also includes a .pi./4-DQPSK differential detector that processes the optimum sample of each symbol for symbol detection.

Abstract: A hand held cellular telephone system including voice storage features which enable the cellular telephone to perform functions similar to a telephone answering device, a battery monitoring system for providing the user with a real time display of the amount of time remaining for use of the cellular telephone in both the standby and conversation modes, and an interface adapter which may be used to provide speakerphone functions, power the cellular telephone, and recharge the battery.

Abstract: A battery monitoring system for a cellular telephone which provides the user with a real time display of the amount of time remaining for use of the cellular telephone in both the standby and conversation modes. The amount of time may be calculated directly from the rate of discharge of the battery or from stored conversion factors corresponding to various states of charge of the battery.

Abstract: A register-modelled radio system comprising a plurality of register-modelled processors having addressable registers for modelling the virtual state of the processor; a serial bus, interconnecting the register-modelled processors for communicating between the addressable registers; and a communications protocol for passing information to or from the addressable registers, whereby the virtual state of a radio portion may be determined or altered by, respectively, communicating information from or to the addressable registers. The communications protocol further comprises an information packet having an address, an operation code, optional data, and an error detection device, such as a cyclical redundancy check packet. The operation code is chosen from the group of primitive operation codes reset, read, write, bit set, bit clear, acknowledge, and negative acknowledge.

Abstract: A telephone interconnect system for a two-way radio communications system is disclosed. A telephone patch interconnect unit accepts dialed digits from a telephone line, encodes them into a data packet, and couples the data packet to a fixed transceiver for transmission to remote units. A remote unit with a digit sequence identification matching the received and decoded dialed digit activates an alert. A remote unit may generate and store digits corresponding to a desired telephone number. The digits are subsequently encoded into a data packet and transmitted to the telephone patch interconnect unit. The interconnect unit accepts, acknowledges and decodes the data packet and couples the resulting digits to the telephone line.

Abstract: In accordance with the present invention, there is provided a register-modelled radio system comprising a plurality of register-modelled processors having addressable registers for modelling the virtual state of the processor; a serial bus, interconnecting the register-modelled processors for communicating between the addressable registers; and a communications protocol for passing information to or from the addressable registers, whereby the virtual state of a radio portion may be determined or altered by, respectively, communicating information from or to the addressable registers. The communications protocol further comprises an information packet having an address, an operation code, optional data, and an error detection device, such as a cyclical redundancy check packet. The operation code is chosed from the group of primitive operation codes reset, read, write, bit set, bit clear, acknowledge, and negative acknowledge.

Abstract: A data signalling system for transmitting signals between at least one primary station and a plurality of secondary stations. The system is well adapted for use in multiple unit radio communications systems capable of noise and data communications. A register model is utilized which permits a highly flexible signalling system compatable with a wide range of communications networks. Data transfer is accomplished using fixed length data packets which are error correction encoded and transmitted utilizing PSK modulation.

Abstract: A general purpose data control terminal which permits multiple terminal control. The terminal is programmable thereby permitting compatability with a wide range of communications systems. The unit is microprocessor based and includes a keyboard, and display, and utilizes acknowledge and retransmission logic for improved reliability.

Abstract: A general purpose data control and information system particularly well adapted for multiple unit radio communications providing reliable enhancement to normal voice systems. The system provides addressing capability along with data transfer and utilizes handshake and retransmission protocol to enhance flexibility and reliability. The system utilizes fixed length signalling packets, with error correction encoding, to permit data transfer, transmitter identification and control and status monitoring.

Abstract: A data signalling system for transmitting signals between at least one primary station and a plurality of secondary stations. The system is well adapted for use in multiple unit radio communications systems capable of noise and data communications. A register model is utilized which permits a highly flexible signalling system compatable with a wide range of communications networks. Data transfer is accomplished using fixed length data packets which are error correction encoded and transmitted utilizing PSK modulation.

Abstract: A communications system central controller which regulates the access of a plurality of remote units to a single communications channel is disclosed. The central controller establishes a period of time wherein a remote unit may request service following the transmission of another remote unit. The central controller interprets the remote unit request for service, stores the request, and grants permission for the remote unit to transmit its message in accordance with the priority in the storage means. The grant of service is revoked by the central controller after a predetermined period of time following the conclusion of the remote unit transmission.

Abstract: A remote unit which transmits and receives messages within a fleet of remote units on a single communications channel shared by a plurality of remote unit fleets is disclosed. Access to the channel is regulated by a central control station which transmits control signals on the channel. To obtain service, a remote unit transmits a request synchronized by one of the control signals. Upon receiving a grant of service from the central control station, the remote unit may transmit a message to its fleet. At the conclusion of the message, an end-of-transmission condition is indicated by the remote unit.

Abstract: A selective calling, paging and priority signalling system for two way communications between at least one primary and a plurality of remote stations. An automatic selective calling mode is provided in which the primary station operator enters the address of the desired unit and activates his microphone. Unmuting data packet will then be transmitted to the addressed remote station, unmuting the remote station. When the transmission ends, a mute data packet is transmitted, remuting the remote station.

Abstract: A digital voice storage mobile control terminal adapted for use in multiple unit land mobile radio communications system. The mobile control terminal utilizes up to eight 64K dynamic RAMs to store up to 42 seconds of speech comprising up to eight separate messages as well as a CVSD encoder-decoder to digitize speech messages.

Abstract: A digital voice storage system adapted for use in a multiple unit land mobile radio communications system. The system utilizes a PSK signalling system with fixed length data packets to control a system capable of multiple message storage of speech at mobile stations. Up to eight 64K dynamic RAMS are used in conjunction with a microprocessor to store up to 42 seconds of speech comprising up to eight separate messages. In addition, the system permits base interrogation of mobiles to determine if a message has been stored for review by the base operator and to determine the remaining recording capacity and total recording capacity of the mobile.

Abstract: An improved digital demodulator and detector for phase-shift-keyed digital signals providing coherent detection with high sensitivity and stability on noisy channels. Digital sampling is used in conjunction with a digital phase locked loop system in which basic time increments are subtracted or added to an equilibrium timing loop to provide simultaneous carrier demodulation and bit recovery.

Abstract: A unique carrier data operated squelch for use with a demodulator detector for phase shift keyed digital signals. The counts transitions in the PSK signal by examining a narrow time window around the phase transitions. The number of data transitions that fall inside and outside the window is correlated with a predetermined threshold. The inventive carrier squelch permits parameter programmability and is particularly suitable for implemenation utilizing a microprocessor.