Abstract: A delay and inverting circuit, connected to the car phone system, is for delaying a status of operation of the car phone system and inverting a signal having a predetermined signal level according to the operation of the car phone system. A switching circuit, connected to the delay and inverting circuit, is for effecting a switching operation in accordance with a signal generated from the delay and inverting circuit. An amplifier, connected to the switching circuit and the car audio system, is for amplifying an output signal generated from the switching circuit and generating a driving signal to the car audio system.

Abstract: A cellular telephone system includes a plurality of base stations which cover a plurality of cells. The system also includes a plurality of portable telephones communicable with the base station over radio frequency channels. A base station covering a given cell transmits an IM control signal indicating that there exists IM interference in the given cell. In response to the IM control signal, each of the portable telephones reduces its receiver sensitivity, so that the IM interference can be alleviated.

Abstract: A plurality of subscriber units are connected to at least two transceiver stations for exchanging information in a time division multiple access mode, in which traffic time intervals are allocated in rotation to a variable number C of channels, where C is dependent on the number and type of units to be connected. T intervals plus one control time interval form a frame, where T is mutually prime with respect to the numbers 2 through C.sub.MAX. M frames form a superframe, where M is the lowest common multiple of the numbers 1 through C.sub.MAX.

Abstract: A narrow band modulation UHF/Microwave communication system comprises a transmit/receive base station having a plurality of transmitter for transmitting information at respective UHF/Microwave channel frequencies to a plurality of remote transmit/receive stations, in which the transmitters at the base station are served in common by a single master oscillator and in which a single reference frequency signal is derived from the master oscillator at the base station and transmitted to all of said remote stations where it serves to provide for frequency locking of the oscillators at said stations to produce synchronization between the frequencies at the base station and the remote stations.

Abstract: In a method and apparatus according to the invention the tuning information determined by a measuring computer (20) is stored in the memory of the radio telephone (1). When the radio telephone is in operation the microprocessor (10) receives from the sensors (14) information e.g. about the temperature, and it selects from its memory tuning information, with which the transmitter (11) power is controlled via a D/A-converter (15). The tuning can be made automatically, without opening the casing of the radio telephone.

Abstract: Dual mode cellular telephone apparatus for communicating in analog or digital modes. A portable unit adapted to communicate substantially only in an analog mode is operable to transmit voice signals supplied from an audio input to a cellular base station and to couple voice signals received from a cellular base station to an audio output. The portable unit, which is capable of operating as a stand alone device, is connectable to a mobile unit adapted to communicate in both analog and digital modes with the cellular base station. When the units are connected, voice signals pass through the mobile unit to and from the portable unit for communication with the base station. A control unit determines whether the mobile unit operates in an analog mode or a digital mode.

Abstract: In a local area network station (12) for a wireless LAN, a threshold level circuit (62) includes a register (134) which stores a threshold value. The station receiver (42) monitors the transmission channel and provides a receive level signal indicative of the signal level received. Transmission of a data frame by the station transmitter (46) is permitted or deferred according as the receive level signal value is below or above the threshold level, regardless of whether or not the received signal derives from a transmission by a station in the receiving station's own LAN. The threshold is dynamically updated whenever the station (12) receives a data frame from its own LAN. An improved utilization of the wireless transmission channel is achieved.

Abstract: A radio communication system comprises plural hand held terminals and a base station communicating with each of the hand held terminals by a two-way radio data transmission. The hand held terminal is set with a system ID number by a proper signal representing the system ID number sent from the base station through a radio data transmission.

Abstract: An apparatus for enhancing hygiene comprises a sensor for generating a first signal upon automatically sensing that an individual has entered a washroom and for generating a second signal upon automatically sensing that the individual has exited the washroom. The hygiene enhancing apparatus further comprises a monitoring device for automatically monitoring an individual upon his entry into the washroom, to automatically determine whether the individual has cleaned his hands. The monitoring device includes a generator for producing a third signal upon a detection by the monitoring device that the individual has cleaned his hands. An alert signal generator is provided for generating an alert signal cognizable by a human being. The alert signal generator is operated or activated by a control unit which is operatively connected to the sensor, the monitoring device, and the alert signal generator.

Abstract: An excavator includes an upper structure swingably supported by a lower structure. A worker position sensor consists of a plurality of radio frequency transceivers provided in the excavator and a radio frequency transceiver carried by each of the excavation workers working within the working range of the excavator. A signal processing unit determines whether the relative distance between each worker and the excavator is either of short distance, slightly long distance or long distance and identifies the position of each worker for each of the predetermined identifying areas. A determining signal from the signal processing unit is supplied to a control unit. The control unit is connected to a drive unit which includes electro-hydraulic proportional valves for energizing actuators for positioning, swing, and traveling of the excavator. This control unit is also connected to a machine sensor which includes a swing angle sensor, a traveling level sensor, and a swing operation lever sensor.

Abstract: A spread communication system comprising a receiver, a diffusion convertor for converting a signal from the receiver, a control signal generator for generating a control signal representing an output level of the diffusion convertor, another diffusion convertor for converting data to be transmitted, a transmitter for transmitting data from the another diffusion convertor and a transmission controller for controlling a transmission level of the transmitter in accordance with the control signal from the control signal generator.

Abstract: An information transmission arrangement comprising transceiver units (1, 2) located in a propagation medium (10) whose attentuation varies as a function of frequency. At least one unit (1) comprise a meter (67) for measuring the level of the received signal in order to influence the frequency variation control (32) of the control oscillator (28) in the send circuit (26, 28) of the other unit (2). This arrangement profits from a monotonic attenuation gradient of the propagation medium (10) having a zone (Z1) in the 50-60 GHz band to control the send level in a simple and effective manner.

Abstract: A communications device in which a control unit and a delay unit transmit a time-shifted acknowledge signal in response to a received message. For the purpose of adhering exactly to the difference in time between receiving the request signal and sending the acknowledge signal, the control unit is connected to a temperature sensor and an adjustment-value memory. By means of the temperature sensor the control unit takes an adjustment value from the appropriate memory address and passes this adjustment value to the delay unit for determining the delay time. A field of application is, for example, mobile radio receivers for car telephone systems.

Abstract: A radio telecommunication apparatus is disclosed which is adapted to, prior to the transmission and reception of control data, transfer its own ID code from an external memory to an internal memory and hold it there and to read the held data which is employed for control data transmission and reception out of the internal memory upon each subsequent transmission and reception of the control data.

Abstract: A serial data communication device of a half-duplex communication system includes two communication units. One of the communication units has a counter for measuring a length of a remaining time during one sending/receiving period set for one-way data transmission (a period during one sending/receiving period W from the time when the communication unit receives all the send data from the other communication unit to the time to start data sending). A send frequency in data sending is determined to as a lower value practicable in the range in which no collision of the data occurs, depending on the length of the measured remaining time. The other communication unit is configured so as to receive the send data of one communication unit to extract the send frequency in synchronization with a serial clock signal having the same frequency as the send frequency and send the data.

Abstract: A digital serial interface system is provided for communicating digital signals including digitized audio between microprocessor-based Control and Transceiver Units of two-way radio communications equipment. The system of the invention essentially comprises three subsystems: (1) an interface in the microprocessor-based Control Unit, (2) an interface in the microprocessor-based Transceiver Unit and (3) a two-way medium for linking the two units. Various signals and audio in the Control Unit interact with a software-driven microprocessor of the Control Unit and are digitized and then translated into a serial format, organized in channel groups through a TDM (Time Division Multiplex)/PCM (Pulse Code Modulation) process and transmitted in frames through a two-way medium to the Transceiver Unit which is also microprocessor-based and incorporates a similar interface. The digital data communicated to the Transceiver Unit then undergoes a reverse process. The Interface System is duplex (bidirectional).

Abstract: An emergency transmitter system is disclosed for enhancing the personal security of individuals within a predetermined geographic area such as a campus, shopping mall or stadium. A plurality of fixed transceivers are located at selected locations within the predetermined geographic area, preferably in a substantially equidistant pattern throughout the area. In a preferred embodiment of the present invention, each fixed transceiver is preferably located in conjunction with a street light in an elevated location. A battery powered low power portable transmitter is then issued to selected individuals, each transmitter including circuitry for transmitting a coded signal associated with a particular individual. In the event of an emergency situation, the portable transmitter is activated, utilizing an irrevocable manual activation switch, and the coded signal is transmitted utilizing the low power radio frequency signal.

Abstract: A communication system which includes a modem and a plurality of controllers has each controller connected to the modem by an interface apparatus, each controller and the modem complying with a predetermined protocol. The interface apparatus comprises a bus which provides a medium to transfer signals between the controllers and the modem. A first interface unit, which interfaces the modem to the bus, implements, a modem-associated multi-state state machine and responds to signals on the bus maintaining the predetermined protocol between the modem and the first interface unit. A plurality of second interface units interface a corresponding controller to the bus. Each second interface unit implements a controller-associated multi-state state machine which responds to signals on the bus and further responds to signals from the corresponding controller, each second interface unit maintaining the predetermined protocol between the second interface unit and the corresponding controller.

Abstract: A communication system which includes a modem and a plurality of controllers has each controller connected to the modem by an interface apparatus, each controller and the modem complying with a predetermined protocol. The interface apparatus comprises a first component, a bus, which provides a medium to transfer signals between the controllers and the modem. A second component provides an arbitration path between said controllers. A first interface unit, which interfaces the modem to the bus, implements a modem-associated multi-state state machine and responds to signals on the bus maintaining the predetermined protocol between the modem and the first interface unit. A plurality of second interface units interface a corresponding controller to the bus.

Abstract: A video broadcasting method and apparatus. The broadcasting method generally includes the steps of selecting one or more channels from a plurality of available channels, and scanning the selected channels for generating signals identifying these selected channels. The channel identifying signals are then fed back to a transmitter unit over a first carrier frequency. The feedback signals are used to selectively identify the channels to be transmitted. The signals from the selected channels are compressed, multiplexed and transmitted over a second carrier frequency to a reception unit, where the signals are demultiplexed and separated into separate channels, and stored for a predetermined period of time. The separated signals are then decompressed, reconstructed and displayed on a real-time basis.

Abstract: A multiplexed synchronous/asynchronous data bus is disclosed in which three bus lines are used to convey bidirectional synchronous data between at least two data devices at a relatively low data rate. Half duplex asynchronous data is applied at a higher data transfer rate to one of the three bus lines when another of the bus lines is held in a logic high state.

Abstract: A mobile radio is disclosed which includes an integrated circuit audio processor which operates under the control of at least one microprocessor. The audio processor provides basic transmit/receive audio filters, tone signaling filters, squelch filters, an RF power level control circuit, a DC voltage measuring circuit, a volume level adjusting circuit, and a transmit level adjusting circuit. In the audio processor, audio bandwidth, tone filter response, squelch filter response and other operating characteristics are adjusted by an incoming data bit stream from the controlling microprocessor. In addition, in response to data received from a microprocessor, the audio processor is controlled, for example, to have its receive audio path closed and its transmit audio path opened to switch from the receive to transmit mode.

Abstract: A system for monitoring presence of persons at preselected monitoring locations. A plurality of local units, one at each monitoring location, determines whether the monitored person is present or absent at the monitoring location and sends report signals via free space radio transmission. A mobile unit, preferably mounted in a vehicle, passes within range of the various local units in order, and hence recovers status information. Desirably, the mobile unit provides a perceptible signal to an officer in the vehicle if the monitored person is absent. Each local unit may be arranged to receive radio signals from a tag carried by the monitored person and to provide an absence indication if the tag signals are no longer received. The same radio receiver as employed to receive the tag signals may also be employed to receive a callout signal sent by the mobile unit.

Abstract: The communications system of the present invention defines a complete feedback path consisting of first and second transceivers and an appropriate signal path. Each transceiver comprises a detector and a signal source capable of generating a signal at one of two frequencies. The detector in each of the transceivers is a two state device tuned to respond only to a predetermined desired difference frequency. If the desired difference frequency signal is present, the detector provides and output signal in a first state; if the desired difference signal is not present, the detector provides an output signal which is in a second state. The signal source can be a voltage controlled oscillator, a pair of single frequency oscillators, a synthesizer, or any signal source capable of being electrically switched between two frequencies. Data can be exchanged between the transceiver pair only when the desired difference frequency is present.

Abstract: A control unit is inserted in the power lines that serve a vehicular telephone and an audio system. A power monitoring circuit detects current increases related to operation of the telephone, either from an incoming "ring" signal or the "off hook" condition in preparation for an outgoing call. The monitoring circuit generates a control signal which is applied to an electronic switching circuit that interrupts the flow of power to the audio system circuits. So long as the telephone is in use, the audio system is disabled. When the telephone returns to the quiescent or stand-by state, the current drawn by the telephone drops substantially below a threshold level of the monitoring circuit and the switching circuit restores the power to the audio system.

Abstract: An avalanche rescue system in which reliable triggering conserves power and permits a high power alarm to be transmitted from a victim to a survivor. Triggering is provided by light sensitive elements on the user, or by a signal transmitted from a survivor. Microprocessor control synchronizes VHF information signal transmission and burst microwave transmission from a victim as well as received signal processing by a survivor. A directional multiple antenna array is switched to provide directional signals displayed to the survivor. A garment is used to affix the system to the person of the user. A unit includes a case and a cover, and the directional antenna array is extended when the cover is opened.

Abstract: An electronic two way signalling apparatus for permitting two or more persons not in line-of-sight with each other to activate transceivers for broadcasting and receiving radio frequency signals alerting those persons of the presence of others within the range of the broadcast signals. The apparatus carried by such persons provides a fixed outgoing radio frequency signal on a random broadcast time of short duration and reception of incoming radio frequency signals at time when a broadcast is silent, and each such apparatus is identical in operation.

Abstract: A system for detecting unintentional operation of a radio transmitter includes an antenna for receiving a r.f. signal and a detector for detecting the absence of presence of a component in the received signal that is indicative of a transmission from a radio transmitter keyed in an operating condition but not being used. In response to detection of such signal component, the detector produces a trigger signal. A delay timer times the duration of the trigger sigal and produces a delayed signal in response to the duration of the trigger signal exceeding a preset time period. An indication circuit produces an operator-alerting indication in response to receipt of the delayed signal informing the operator that the transmitter is unintentionally keyed in an "on" condition. The system also has a d.c. power source for supplying power to the detector, delay timer and indication circuit to operate the same.

Abstract: An interface device for connection between a facsimile reproduction machine and a simplex radio includes a receiving circuit and a transmitting circuit. A switch connects an appropriate one of the circuits to the machine. A control circuit monitors the change in the mode of operation of the machine and operates upon the switch to cause a corresponding change of connection to the machine. The control circuit also operates upon the transceiver to condition it to a transmit mode upon the transmit circuit being selected.

Abstract: An improved automatic/remote RF instrument monitoring system including a plurality of transponders configured to operate with one of a plurality of parameter sensing instruments remotely located from an interrogate/receiver. The interrogate/receiver transmits RF transponder activation signals in the form of a tone modulated onto a carrier. In response to the activation signals, the transponders "wake-up" and transmit an RF transponder signal which is received and processed by the interrogate/receiver. The transponders include a transmission enable circuit which initiates transmission of the RF transponder signals at random times after receipt of the activation signals. The RF transponder signals are formed by a plurality of spaced transponder information packets.

Abstract: A radio communication device comprises a portable communication device and a power amplifier device adapted to accommodating the portable communication device thereinto for amplifying a transmitter output therefrom. The radio communication device further comprises a detector circuit for detecting that an electrical coupling between the portable communication device and the power amplifier device, thereby effecting a control such that the transmitter output power level is kept at a minimum input level required for the power amplifier device. Thus, this can suppress exceesive heat generation in the communication device when the portable communication device is used by being accomodated in the power amplifier device.

Abstract: The present invention relates to a land mobile telephone system with enhanced operability realizing both the loud-speech and closed-speech operations by the single handset. The handset is installed detachably in a pad of a steering wheel of an automobile and having a power terminal for feeding electric power from an automobile-equipped battery to said handset devices when said handset is seated in the steering wheel pad, said controller having a speed mode selector which selects a loud-speech mode when said handset is seated in the steering wheel pad or selects a closed-speech mode when said handset is taken out of the steering wheel pad.

Abstract: A cordless telephone includes a base unit and a handset unit. When the handset unit is mounted on the base unit, an identifying code is automatically generated and stored in both units. Thereafter, when an incoming or outgoing telephone call is initiated, the two stored identifying codes are compared, and the telephone call proceeds only if the two identifying codes are identical. The new identifying code is generated as a counted value in accordance with a predetermined time following the mounting of the handset unit of the base unit. By having the predetermined time vary from telephone to telephone, the identifying codes will also vary, eliminating crosstalk interference and the risk of wiretapping.

Abstract: A cordless telephone utilizes internally generated identifying codes to reduce crosstalk and the risk of wiretapping. When the handset unit is mounted on the base unit, a new identifying code is automatically generated and stored in the base unit, and then transmitted to the handset unit, which also stores it. When an incoming or outgoing telephone call is initiated, the two identifying codes stored in the base unit and the handset, respectively, are compared and, if they are not identical, the telephone call is cut off. Advantageously the identifying codes are randomly generated.

Abstract: A headset for communication with both FM and AM circuit signals comprising a first earphone for receiving only FM signals and a second earphone for receiving only AM signals and first and second switches associated with the headset and coupled to the FM and AM circuits for selectively transmitting a response to either of the received signals on a corresponding one of the FM and AM circuits.

Abstract: A compact and simple to operate transceiving device used by law enforcement officers, security agents, military personnel and the like to prerecord an emergency message prior to leaving his vehicle. In an emergency situation, the apparatus will automatically affect transmission of the above message to a central station if the user did not return to his vehicle in a preset amount of time.

Abstract: A wireless telephone communication system 10 is provided in which a portable unit 12 communicates with a base unit 11 over a wireless (radio) communication link 15. Access to a telephone network 15b by the portable unit 12, via the base unit 11, is permitted when the base and portable units have corresponding ID codes stored therein. The base ID code is hardwired into the base unit 11, and the portable unit 12 learns its ID code from the base unit in response to mechanically coupling the base and portable units together via plug and socket assemblies 28 and 45. The base and portable units each have associated microprocessors 22 and 40 which implement the transfer of an ID code to the portable unit from the base unit via conductors (24'-42') which are part of the plug and socket assemblies. The plug and socket assemblies, when mated, also provide a connection between a battery charging supply circuit 25 in the base and a battery 46 in the portable.

Abstract: An out-of-range monitor and alarm system that may be used by a convalescent home or the like to alert an attendant in the home that a supervised person has walked beyond a predetermined prescribed distance. The system includes a base unit that transmits a signal at a frequency F1 to a receiver in a mobile unit carried by the supervised person. The receiver includes a threshold circuit that is adjustable to correspond to the prescribed distance and produces a threshold output signal whenever the F1 signal detected by the receiver drops below the threshold level. In response to the threshold output signal, a transmitter in the mobile unit produces an F2 output signal to a receiver in the base unit, which in turn sounds an alarm indicating that the mobile unit has lost adequate F1 signal strength, as determined by the threshold adjustment, by exceeding the range prescribed for the supervised person.

Abstract: A system is disclosed which includes a radio transceiver and a radio broadcast-band receiver housed in a package that is supported by a helmet of the type worn by mobile users such as motorcycle, bicycle, moped and skateboard riders and the like; or by non-mobile users such as policeman, fireman, construction workers and the like. In the absence of signals to or from the transceiver the user listens to radio broadcasts. Voice actuated circuitry disables the radio receiver and enables the transceiver transmitter for message transmission by the user to a remote station against a background of silence, or against a background of the user's voice. Other circuitry is responsive to a message from a remote station received by the transceiver receiver for disabling the radio receiver so that message is heard by the user against a background of silence.

Abstract: Branch telephone connection control signal communication between a dialling control board mounted on a steering wheel but held in a stationary state irrespective of a rotation of the steering wheel and an electric controller disposed at a position remote from a steering mechanism, the electric controller is connected to a mobile telephony device on a road-vehicle. The dialling control board is supported by a steering drive shaft through a toothed wheel mechanism, so that it remains stationary regardless of a rotation of the shaft. The control board and the electric controller are electrically coupled to each other through a combination of slip rings and brushes. The dialling control board and the electric controller each include an FSK modulation circuit, an FSK demodulation circuit and a microprocessor for controlling transmission or reception of the electric signals. Key inputs on the dialling control board are encoded by the dialling control board and then transmitted to the electrical controller.

Abstract: A high speed bus structure is described which employs an ordinary flat ribbon cable. ECL receivers are coupled to conductor pairs of the cable through resistors which change the capacitive load of the ECL receivers to a resistive load. The receivers are coupled to the cable through a plurality of connectors having spaced-apart pins. The pins in each connector engage less than all of the conductor pairs, thus a plurality of connectors are required to completely couple receivers to all the conductors in the cable. This connector arrangement substantially reduces the parasitic capacitance loading on the cable. The invented high speed bus is able to effectively function at 100 MHz with 80 feet of cable and with 16 receivers coupled to each conductor pair.

Abstract: A radiotelephone system having a control transmitter unit which includes a control unit having operating keys, a channel indicator device, a function indicator device and a loudspeaker/microphone device, the control transmitter unit including an ultrasonic or infrared transmitter for the transmission of the function signals required for operation of the radiotelephone system, the radiotelephone system further having a receiver unit provided with an ultrasonic or infrared receiver for actuating function and indicator devices.

Abstract: All messages broadcast through a two-way radio by a police officer from his vehicle, are recorded on an endless tape loop of a playback recorder. An alerting signal generated by a pretuned oscillator is simultaneously recorded on the tape with each message. Playback operation of the recorder is initiated by a remote radio trigger device so as to replay and transmit the recorded message and altering signal through the vehicle radio for a timed duration.