Abstract: A data communication terminal (102) transmits messages to a plurality of data communication receivers (106), and has an input for receiving messages and assigning the same into a plurality of transmission frames which are assigned for transmission to the plurality data communication receivers. The data communication terminal (102) comprises a first memory (210) for storing the received messages, a timer (214) for generating periodic timing signals, a controller (204) responsive to the periodic timing signals, for recovering the stored messages and queueing the same into a second memory (1910) having a predetermined transmission frame queue capacity. A monitoring circuit (1902, 1908) monitors the transmission frame queue capacity of the second memory (1910), and expected transmission frame queue capacities for one or more subsequent transmission frames.

Abstract: A wristworn receiving device suitable for being worn about a wrist comprises a receiver (404) for receiving radio frequency signals on a particular operating frequency, a housing (142) for enclosing the receiver (404), a first wristband section (102) including a first wristband loop antenna portion (118) and a movable clasp member (122), and a second wristband section (104) including a second wristband loop antenna portion (134) terminated in a fixed clasp member (140). The first (118) and second (134) wristband loop antenna portions are partially resonated at the operating frequency. The second wristband loop antenna portion (134) is coupled to the first wristband loop antenna portion (118) and is positioned by the movable clasp member (122) at first (204) and second (202 or 206) positions along the first wristband loop antenna portion (118) so as to form a resonant loop antenna which remains substantially tuned to the operating frequency at the first (204) and second (202 or 206 ) positions.

Abstract: A digital tone detector utilizes pseudo sinusoidal quadrature reference signals in combination with a unique summation rule for summing the resultant quadrature accumulations to obtain a substantial improvement in the sidelobe responses of the filter. The digital tone detector also utilizes a "stepped" observation window to further provide a substantial improvement in the third harmonic response of the filter. The digital tone detector can be implemented using a hardware implementation, a combination hardware and microprocessor implementation, and a microprocessor only implementation.

Abstract: An alerting system for a selective call communication receiver (10) which includes a battery (26A, 26B) for supplying energy at a first supply rate and a receiver (14) coupled thereto for receiving transmitted selective call message signals includes a decoder (16), a power source (44), an annunciator (34) and a charging circuit (36). The decoder (16) is coupled to the battery (26A, 26B) and decodes the received selective call message signals and generates an alert signal output in response to the received selective call message signals. The power source (44) is capable of being charged and supplies energy at a second supply rate. The annunciator (34) is coupled to the power source (44) and is responsive to the alert signal output for providing a sensible alert. The annunciator (34) consumes energy at the second supply rate when providing the sensible alert.

Abstract: A control station 12 initiates a system timing signal transmission which is re-transmitted from a satellite 14. In response to receiving the system timing signal, the control station 12 then generates a time correction factor which is distributed to a plurality of transmission stations 16, 18. The transmission stations 16, 18 in response to receiving the system timing signal transmission and the time correction factor distributed from the control station 12 generate a time adjustment factor which is used to correct the local transmission clocks 36, 36', thereby providing time synchronization of data transmissions generated from the transmission stations 16, 18.

Abstract: A communication system is described which provides call queueing between a base station (400) which does not have a control channel and a plurality of portable communication handsets (401). The base station (400) determines when all channels are busy, and following one becoming available, transmits a first predetermined code. All portable communication handsets (401) which attempted to communicate with the base station (400) when all channels were busy, sets a queue mode flag, and starts a timer (455, 461). When a first predetermined code is detected by any handset (401) having attempted to establish communication with the base station (400), the first timer (455, 461) continues, and a second timer (455, 461) operating at a second rate is started at the value established by the first timer (455, 461). When the second timer (455, 461) value reaches a predetermined value, the handset (401) proceeds to attempt to establish communication with the base station (400) on the channel that became available.

Abstract: A signalling system provides for efficient reception of message by a plurality of Earth based selective call receivers such as pagers. The signals are transmitted from satellites in orbit above the Earth. Each satellite includes a multiple lobe antenna capable of transmitting messages to a selected portion of the surface of the Earth. Methods for conserving satellite transmission power in the communication of message information are described. Furthermore, a signalling protocol transmitted by the satellite provides for power conservation by Earth based selective call receivers. Additionally, a method enabling an area of the Earth to receive messages from multiple satellites is described.

Abstract: A simulcast transmission system (10) and method provides for time synchronizing data transmissions from a plurality of transmission stations (16, 18). The transmission stations (16, 18) include transmission clocks (36) for controlling the time of transmission of synchronization timing signals and data. The synchronization timing signals indicate a local time of transmission which are transmitted in response to system timing signals received from the control station (12). The control station (12) comprises apparatus (20) for generating and distributing the system timing signals, apparatus (26) for receiving the synchronization timing signals from the transmission stations, and apparatus (20, 22, 28) for generating and distributing time adjustment factor signals to the transmission stations (16, 18) in response to receiving the synchronization timing signals. The transmission clocks (36) are adjusted in response to the time adjustment factor signals for controlling the time of transmission of the data signals.

Abstract: An enclosure latch system includes an insertable member (106) connected to a first enclosure section (102), and a mating recess (108) within a second enclosure section (104) for engaging with the insertable member (106), thereby latching the first and second enclosure sections (102, 104) together. The insertable member (106) includes an extender member (202) connected at an attachment end to the first enclosure section (102) for extending the insertable member (106) into the second enclosure section (104), and a latch tooth (204) protruding from the extender member (202) near a free end. The latch tooth (204) has a mating surface (206, 208) that tapers from flat on a first side to cylindrical on a second side opposite the first side for latching the first and second enclosure sections (102, 104) when the latch tooth (204) is in the mating recess (108).

Abstract: A battery saving apparatus selectively supplies power to each receiver function of a battery powered communication receiver at predetermined time intervals prior to and continuing therefrom for enabling the reception of the coded message signals with each receiver function being powered only as long as is required for each receiver function to stabilize prior to the reception of the coded message signals.

Abstract: In a wireless communication system comprising a plurality of fixed communication units (FCUs) (102) and portable communication units (PCUs) (120), each comprising an encryption synchronization counter (ESC) (314, 414), the PCU and FCU having a digital transmission format (201), a method of maintaining encryption and decryption throughout a hand-off is shown, comprising the steps of:(a) loading (708) during a hand-off initiation a continuation value for a second FCU ESC; and(b) incrementing (709) synchronously the second FCU ESC and the PCU ESC, starting from the continuation value and beginning at the time of hand-off completion.

Abstract: A dual mode communication receiver a receiver for receiving information transmitted in a first and second modulation format on a common channel, a first demodulator for detecting information transmitted in the first modulation format, and a second demodulator, responsive to the information detected in the first modulation format, for detecting information transmitted in the second modulation format. A power conservation circuit is also provided for selectively supplying power to the first and second demodulators for enabling the detecting of the information transmitted in the first modulation format and the second modulation format, respectively.

Abstract: In a heterodyne receiver having more than one selectable receive frequency and having at least one intermediate frequency circuit (102) capable of operation on at least two intermediate frequencies, a method for selecting one of the at least two intermediate frequencies is shown. The selection method includes selecting (402) one of the more than one selectable receive frequency, and then selecting (408, 410, 504, 506, 510, 512) at least one of the at least two intermediate frequencies for each of the at least one intermediate frequency circuit in response to the selected receive frequency. The selection of the intermediate frequency for each of the at least one intermediate frequency circuit is made such that the selected intermediate frequency does not cause the generation of one or more undesirable spurious frequencies as a result of mixing the selected receive frequency and the selected intermediate frequency.

Abstract: A method and apparatus for providing extended battery saving operation in a conventional selective call signaling protocol, such as the POCSAG signaling protocol includes the transmission of an ordered batch identifier code word in the first frame following a preamble transmission. Upon detection of the ordered batch identifier code word, those selective call receivers capable of extended battery saving operation would supply power to the receiver only during those batches assigned to the receiver group to which the selective call receiver belongs, such as for every second or fourth batch transmission. The method for providing extended battery saving capability is transparent to conventional selective call receivers operating within the system.

Abstract: A switch includes a housing (36) which retains an elastomeric actuating member (38) having an actuating portion (46) and a contact portion (37). The contact portion (37) deforms in a first direction (52) in response to a force exerted on the actuating portion (46) in a second substantially different direction (e.g. orthogonal thereto)(48). The housing (36) comprises a rigid member in contact with a side of the elastomeric actuating member (38) opposite the actuating portion (46) on which the force is exerted.

Abstract: A symbol synchronizer for a communication receiver receiving multi-level data signals includes a reference clock generator for generating a reference clock signal having a predetermined time period, a state change detector for detecting state changes occurring within the received multi-level data signals over the predetermined time period to enable determining a time location corresponding to the detected state change wherein the time locations are assigned predetermined numeric values corresponding to the time locations determined, an accumulator for accumulating a time location for the time locations selected, and a phase adjusting circuit which is responsive to the time location count for adjusting the phase of the reference clock signal relative to the received multi-level data signal.

Abstract: A transmitter system for transmitting coded message signals on a plurality of channels of which at least one channel to be assigned to each of a plurality of geographical areas. The coded message signals include channel identification information and message information being transmitted in a sequence of coded transmission slots on each of the plurality of channels. The sequence of coded transmission slots are transmitted offset in time such that a particular transmission slot is not substantially simultaneously transmitted on any of the plurality of channels.A receiver capable of receiving the coded message signals during a predetermined coded transmission slot being transmitted on the plurality of channels is also described.

Abstract: Communication between first (38, 40 or 42) and second (38, 40 or 42) portable radiotelephone transceivers is provided in a radiotelephone communication system by generating a paging message (500-512) in response to the first transceiver (38, 40 or 42) registering with a first telepoint base station (32, 34 or 36). The paging message (500-512) is directed to the second transceiver (38, 40 or 42) for which communication is requested, and identifies the first telepoint base station (32, 34 or 36) and the first transceiver (38, 40 or 42). Upon receiving the paging message (500-512), the second transceiver (38, 40 or 42) registers with a second telepoint base station (32, 34 or 36), downloading the information identifying the first telepoint base station (32, 34 or 36) and the first transceiver (38, 40 or 42).

Abstract: A transmitter for transmitting digital information to a communication receiver employing a post detection low pass filter having a predetermined filter transfer function comprises a memory, a pulse recovery circuit, and a transmitter section. The memory stores an optimized electric pulse which is defined by the combination of an electric pulse exhibiting minimum intersymbol interference characteristics and the reciprocal transfer function of the predetermined post detection low pass filter transfer function of the communication receiver. The pulse recovery circuit recovers the optimized electric pulse from the memory, and generates a sequence of optimized electric pulses corresponding to the digital information to be transmitted. The digital information to be transmitted is then transmitted by the transmitter section.