Abstract: A coin operated telephone station is provided with apparatus for detecting hen a called party has answered a call (initiated at the coin operated telephone station) by the measurement of incoming signal energy on the telephone line. The apparatus includes hardware and software that cooperate in providing efficient and reliable detection of called party answer for the purpose of accurately charging telephone users. A microprocessor samples the output from each of three specialized energy detectors every 20 milliseconds to determine whether called party answer has occurred. The energy detectors include: (1) call progress tones in the frequency band 200-700 Hz approximately; (2) special information tones; and (3) broadband energy in the frequency band above 200 Hz. Additionlly, the time duration of the call progress tones and the quiet intervals between them are measured and used in the answer detection process.

Abstract: In a radio telephone system comprising a radio telephone set utilizing a rechargeable battery, and a base unit connected to the radio telepone set through a radio channel for exchanging a speech signal between the radio telephone set and a wired telephone line, there are provided a detector for detecting the charged state of the battery, a terminating device responsive to the output signal of the detector for terminating the radio channel between the radio telephone set and the base unit.

Abstract: A method and apparatus for utilizing voice channel transceivers as temporary scanning receivers in a handoff event for a cellular radiotelephone system is disclosed. Voice channel transceiver identifications are stored in link lists according to priority, sectorization, and last use. When a signal strength measurement is required, those cell sectors having available voice channel transceivers are identified and a table providing optimum transceiver selection is utilized to select those voice channel transceivers which will make the signal strength measurement.

Abstract: This invention relates to a roadside emergency system. The systems includes a roadside station which has a telephone unit similar to a mobile telephone set for a cellular mobile telephone system. When the unit is activated, it automatically generates radio signals which cause a mobile telephone switching office to dial up an emergency station (such as a highway police station). The office also automatically establishes a channel for voice communication between the roadside station and the emergency station. The roadside station is further provided with a back-up battery and an alarm to prevent tampering.

Abstract: A method and apparatus for managing an electronic radio telephone lock in which the electronic lock can be rendered operative or inoperative only by first entering a predetermined code so as to prevent unauthorized use as well as accidental or unauthorized locking, code changes, etc.

Abstract: A trunked communication signalling method is provided by a unifying signalling protocol in which subscribers request communication channels using only their individual IDs encoded into a single ISWs. The central decodes the call request, extracts the requesting subscriber's individual ID, which is cross referenced to determine the subscriber's talk-group affiliation(s). If the requesting subscriber's affiliation(s) are not known, the central commands the subscriber to transmit its affiliation using dual ISW signalling. In another aspect of the present invention, each subscriber automatically informs the central of a change in talk-group affiliation, thereby providing continual affiliation updates. In this way, many thousand subscribers are afforded access to a single trunked system, and control channel traffic congestion is minimized.

Abstract: For a transmitter of a mobile station of a radio communication network which is typically a mobile radio telephone network, a power supplying arrangement is intermittently energized before being continually energized to allow the transmitter deliver a speech signal to another mobile station through a base station of the network. More particularly, the power supplying arrangement is temporarily energized in response to a down-loop indicating signal, and transmits a specific up-loop signal after which it is deenergized immediately subsequent to transmission from the transmitter of a known pre-call response signal. After this operation, it is preferable that the power supplying arrangement is intermittently energized upon reception of an intermittent succession of call signals and then continuously energized after the mobile station is put into an off-hook state for transmission of the speech signal.

Abstract: Unnecessary control channels are eliminated in a mature cellular radio telephone RF communications system by sharing control channel transceivers and control channels between original omni-directional cells and subdivisions of those original cells. A control channel is allocated to the original omni-directional cell, and subdivided cell areas are not provided with their own control channels. One or more voice channels are allocated to the original omni-directional cell, and the subdivided cell areas also have voice channels allocated to them. Calls are initiated between mobile transceivers and the original omni-directional cell. Locating receivers associated with the subdivided cell areas determine which subdivisions particular mobile transceivers are located within. Subsequently, calls are handed off fron the original omni cell to an appropriate subdivision.

Abstract: A method for controlling the amount of the exposure of a television camera whereby a luminance signal from only a selected portion of an overall photometric range of the camera is employed for adjusting the exposure. A first signal is produced specifying the selected photometric range. In response to this signal, and further in response to horizontal and vertical synchronizing signals from the television camera in synchronization with the scanning of an electron beam in the camera, a range signal is produced when the scanning beam is within the specified photometric range. The luminance signal outputted by the television camera only at that time is employed for exposure control.

Abstract: Wrong handoffs in a cellular radio telephone RF communications system can be minimized or eliminated without increasing locating receiver equipment requirements, field strength measurement time or system response time. Field strength measurements are made at handoff candidate cells and also at cells neighboring (geographically proximate to) those candidate cells. A weighted average of the measured field strength of the candidate cell and the field strength measured in cells neighboring the candidate cell is calculated for each candidate cell (the field strengths measured by neighboring cells may be multiplied by a weighting factor of 0.5). The weighted averages for the candidate cells are compared, and the candidate cell corresponding to the highest average is selected to handle the mobile transceiver call.

Abstract: Disclosed is a communication system of the type adapted to communicate a message substantially simultaneously between a plurality of fixed location sites having respective radio coverage areas. The system has an arrangement comprising first and second radio frequency transceiver means located at respective first and second sites. The first radio frequency transceiver means is designed for operating on a first set of frequencies. The second radio frequency transceiver means is designed for operating on a respective different set of frequencies than the first set of frequencies. The second radio frequency transceiver means has means for receiving and converting the first set of frequencies to the respective different set of frequencies.

Abstract: A system incorporating a cluster of several telephone stations or terminals to interface with one or more frequently called remote data stations for economy of dial-up connection in accommodating communication with multiple terminals of the cluster during a single call to a remote station. With a call from one terminal to a remote data station, a transmit-receive unit interfaces the cluster with the data station setting the terminals in the cluster in a polling sequence to accommodate additional communications. The system preserves an "off-hook" state polling the individual terminals in the cluster to accommodate further communication from the cluster terminals to the central data station. Polling is facilitated by a cluster counter in the transmit-receive unit coordinated with logic indicating the state of each terminal in the cluster.

Abstract: A multiple access radio telephone system is connected to a telecommunication switching system and serves a group of N remote stations through M two-way radio channels (where M is smaller than N). The remote stations have corresponding subscriber line terminals in the switching system and are accessible to one of the two-way radio channels selected by a concentrator. For efficient channel utilization, the concentrator establishes a full-duplex mode connection between one of the corresponding subscriber line terminals of the switching system and the selected two-way radio channel in response to a request for an extragroup call and establishes a half-duplex mode connection between two of the remote stations through the selected two-way radio channel in response to a request for an intragroup call.

Abstract: A multifunctional telephone capable of memorizing alphabetical characters and telephone numbers includes digit and function keys and a multi-row display unit. The lower row of the display is capable of displaying three groups of letters, A-I, J-R and S-Z above digits 0-9 printed on the face of the telephone. By pressing a corresponding digit key, a letter may be displayed on the upper row of the display. The upper row of the display is capable of showing a name while the lower row can display a telephone number. After the information has been entered into the telephone, it will be stored in memory. After pressing certain function keys, the telephone can search the memory for all information starting with a certain letter. This information will be sequentially displayed and may be automatically dialed after activation of certain other keys. Rather than displaying alphabet characters, "KATAKANA" characters or other symbols may be shown.

Abstract: An improvement in telephone equipment which enables a user to cancel the wrong digit of a misdialed number regardless of its position in the number without cancelling other digits in the number.

Abstract: A cordless telephone system includes a control unit having a speaker, a microphone and control circuitry for selective operation in a "normal" mode for communications between the handset and an outside party, a "local answer" mode for communications between a party at the control unit and an outside party, an "intercom" mode for communications between parties at the control unit and the handset and a "3-way" mode for communications between parties at the control unit and handset and an outside party. A microprocessor so responds to ring detect, control and switch-generated interrupt signals as to obtain the desired communications.

Abstract: A coaxial loudspeaker system is described wherein the high frequency horn which lies within the lower frequency speaker or cone, is constructed to avoid the "shadow effect" wherein there is a large drop in the magnitude of the response of the low frequency speaker over a narrow frequency bandwidth due to diffraction effects caused by the presence of the horn. The horn is formed with a group of slots near its wide end, to provide an opening for the passage of lower frequency sounds into the axial region of the cone which would otherwise be blocked by the horn.

Abstract: A paging communication system is configured so that a plurality of receivers are called by group in response to a paging signal transmitted from a base station. The base station is provided with first circuitry comprising a plurality of timers for counting the number of transmissions to each receiver, and second circuitry operative to transmit a first kind of data indicating that the information code assigned to each of the particular receivers is masked and a second kind of data for restarting the ordinary receiving process with respect to the masked information code. Each receiver is provided with a decoder circuit operative in response to the first kind of data to inhibit the ordinary receiving process with respect to the masked code and operative in response to the second kind of data to restart the ordinary receiving process.

Abstract: Disclosed is a signalling system wherein a private call initiating trunked subscriber enters a private ID number on an entry means. The trunked subscriber unit decodes the entered number and forms the ID code required to request a channel. The central controller receives the request and encodes an appropriate channel grant for a trunked private call. In another aspect of the present invention, the called subscriber unit may decode and display the ID of the calling subscriber.

Abstract: A carrier current telephone system is provided for buildings. Transceivers are located where desired. The transmitter portion includes means for establishing a carrier signal and applying the same to the AC circuits in the building. Further means are provided for generating a subcarrier signal which is encoded on the carrier signal by frequency modulation of the carrier. Further means are provided for encoding the audio or data signal upon the subcarrier signal by frequency modulation of the subcarrier. Exclusive-OR gates are used in a voltage controlled oscillator for the subcarrier signal generator. Unique phase lock loop FM demodulators are used. Each comprises one CMOS 4070B exclusive-OR gate package, five resistors, one potentiometer, and three capacitors, with one of the exclusive-OR gates performing the phase detector function.