Abstract: In a radio broadcast system constituted by a base station and a plurality of subsidiary stations located at various portions around the base station, each subsidiary station includes a detection unit for detecting an error in received data, and a unit for transmitting a burst retransmission request signal (NAK signal) upon detecting an error in the received data, and transmits no signals for a predetermined limited time, except the NAK signal for indicating reception of broadcast data containing an error. The base station either detects the NAK signal within the limited time or regards detection of a radio carrier having a predetermined time length as detection of the NAK signal.

Abstract: There is disclosed a method for controlling the position of a mobile host in a local area network (LAN), whereby the movement of the mobile host out of a certain LAN can be quickly detected even when the mobile host transmits no frames and invalid traffic can be reduced. A server 3 duplicates a learning function table in a bridge device 2 at each specified time. Location confirmation is performed for the currently connected mobile host based on this duplicated information at each specified time. If the mobile host gives no response to the location confirmation, the movement of this mobile host is determined and the learning function table in the bridge device 2 is renewed. Thus, even when the mobile host is moved out of the LAN and no frames are transmitted therefrom, the movement of the mobile host can be quickly detected and invalid traffic can be reduced.

Abstract: In a radio conference system of the present invention, a hub station 1 sends information to a plurality of terminal stations 2 while adding an error checking code thereto. The terminal stations 2 each sends, on detecting an error out of the information received from the hub station 1, a resend request signal including an ID (Identification) code assigned to the terminal station. The hub station 1 counts the number of times of receipt of the resend request signal on a terminal station basis. When the number of the resend request signals received from any one of the terminal stations 2 exceeds a preselected value, the hub station 1 displays alarm information indicative of the above terminal station.

Abstract: In an echo suppressor for suppressing an echo resulting from acoustic coupling in a telephone apparatus, an attenuator attenuates a transmission signal level with reference to a first level signal representative of a level of a reception speech signal which is supplied to the telephone apparatus. Supplied with the reception speech signal through an input terminal, the first detecting arrangement detects the reception speech signal to produce the first level signal. It is a matter of course that a receiver converts the reception speech signal into a reception speech sound. A microphone produces a transmission speech signal in response to a transmission speech sound.

Abstract: In a speech decoding apparatus (100) supplied with an input speech signal (101) comprising successive blocks, each comprising a digital speech signal and an error detecting code signal, an error detector (8) detects an error in the digital speech signal by the error detecting code signal for each block to produce error detection pulses whenever the error detector detects the error. The error detector also produces the digital speech signals of the blocks. A speech decoder (9) decodes the digital speech signals of the blocks into an analog speech signal. A measuring circuit (102) measures, as a measured value, the number of the error detection pulses during a predetermined time interval. A comparator (15) compares the measured value with a reference value to produce a command signal when the measured value is greater than the reference value. A generator (12) generates an alarm signal in response to the command signal.

Abstract: A mobile telephone usable both as a portable and as an installed telephone, capable of saving battery power when used as a portable telephone, and safely starting up voice-dialing when used as an installed telephone. Discriminating circuit (3, 3A, 14) discriminates which use the telephone is now in, portable or installed. In the former use, start-up circuit (7, 15) is manually activated to supply power from battery pack (1) to voice-dialing unit (8). The power supply is cut off in response to reset signal R supplied from the voice-dialing unit when voice-dialing ends. In the latter use, voice-dialing unit is kept switched on to the vehicle battery and ready for start-up in response to voice input.

Abstract: A portable radio telephone set comprises a telephone number generating apparatus and a telephone number transmitting apparatus which are preferably contained in a pencil shaped body. The telephone number generating means generates a telephone number signal, for instance, by sensing the motion of a ball provided on a lower end of the body. The ball is moved to draw a telephone number on a surface of an article. The telephone number signal is modulated in the telephone number transmitting apparatus to be transmitted to air by an antenna which is provided on an upper end of the body.

Abstract: In a speech recognition system, a method for deciding an input pattern as one of reference patterns includes steps for calculating dissimilarities of the input pattern and the reference patterns and selecting a particular one of the dissimilarities which is lower than a threshold value. In order to reduce noise accompanying an input speech pattern in the input pattern, an average noise level is detected from an input pattern before the input speech pattern is detected and a noise factor is produced corresponding to the average noise level. The dissimilarities are multiplied by the noise factor to produce products and then the products are compared with the threshold value to recognize the input speech pattern. According to one aspect of the speech recognition system, particularly the system using the known clockwise DP matching with a beam search technique, the beam width factor is determined as a function of the noise level.

Abstract: An analog switch is provided in a phase-locked loop (PLL) synthesizer using direct digital synthesizer (DDS) circuitry, for opening a PLL. The PLL is closed to make operative the DDS circuitry and a fixed frequency divider within an idle time slot of each time-division multiplexing (TDM) frame. For the rest of the frame, the voltage-controlled oscillator within the PLL is held in a "hold state".

Abstract: An electric machine such as a telephone set, a facsimile machine, etc. installed in a vehicle is supplied with an electric power from a power supply. The power supply is a battery which is charged from a generator driven by an engine of the vehicle, when the engine is rotated. On the other hand, the power supply is a secondary battery which is charged from the battery, when the engine is not rotated.

Abstract: An apparatus for controlling a power supply of an electric machine in a vehicle comprises primary and secondary power supplies for supplying an electric power to the electric machine. In an engine-off state the primary power supply is selected as a power supply for the electric machine when an electric power consumption of the electric machine is over a predetermined value, indicating an operating mode, and the secondary power supply is selected when the consumption is below the predetermined value, indicating a waiting mode. Therefore, the absentee receiving of facsimile information, the absentee recording of telephone message, etc. are carried out, even in an ignition-off state. The secondary power supply is used mainly in the case that the electric machine is in waiting mode, so that the complete exhaustion of the secondary battery can be prevented.

Abstract: In a management system for managing a plurality of terminal endpoint identifiers which are to be assigned to terminal equipment units, an up-down counter is selectively operable in a count-up mode and a count-down mode to count the number of the terminal equipment units which are currently practically connected to the management system and to produce a count signal and to which the terminal endpoint identifiers are assigned, respectively. A read-only memory memorizes a first threshold value and a second threshold value greater than the first threshold value. A comparator compares the count signal with the first threshold value to produce a coincidence signal when the count signal is coincident with the first threshold value. On production of the coincidence signal, the terminal equipments to which the terminal endpoint identifiers are assigned are monitored by a central processing unit to judge whether or not the terminal equipments in question are actually connected to the management system.

Abstract: An ISDN network termination unit for connecting a user's bus line connected to a plurality of terminal equipments and a subscriber line extending from an exchanging office receives and transmits a D channel signal from one of the exchanging office and each terminal equipment to the other to thereby establish a data link between them on the D channel. The D channel signal is provided with an identifier code field. In order to establish a data link between the terminal equipments on the D channel without use of the subscriber line and the exchanging office, the ISDN network termination unit is provided with an identifier code holder for holding a predetermined identifier code and a deciding circuit for deciding whether or not the identifier code in the D channel signal from a specific one of the terminal equipment is equal to the predetermined identifier code.

Abstract: In an ISDN system comprising a plurality of DSLs each having a plurality of DTEs and an ISDN switch having a TEI list, a multiplexer is used for enabling each DTE to access the ISDN switch through a single primary rate DTL in the time division technique. The multiplexer comprises subscriber interfaces connected to DSLs, respectively. The subscriber interface has first TEIs assigned to DTEs on the corresponding DSL and has a first data link with each DTE on the basic interface D channel using a first LAPD frame signal with the first TEIs. The subscriber interface has a second TEI assigned thereto and registered in the TEI list in the ISDN switch. The subscriber interface derives information field from the first LAPD signal and forms a second LADP frame signal having the second TEI and the derived information.

Abstract: A radio communication system comprises a base station for periodically transmitting a power saving signal and an information signal, a repeater station for relaying the signals, and a plurality of terminal stations for communicating with the base station through the repeater station. The repeater station includes power saving circuitry which responds to the power saving signal by cutting off power supplies to its major power consumptive components during a preset interval which alternates with an active interval during which power is supplied to the components.

Abstract: A multiple access communication system comprises a central station connected to an end office switching system and a remote station which serves N subscriber telephones through respective line interface circuits. The remote station provides concentration by switching N subscriber interface circuits to M (where M is smaller than N) trunk circuits which are connected through transmission facilities to M trunk circuits of the central station. The central station provides deconcentration by switching its M trunk circuits to end-office N subscriber line interface circuits. In response to a called subscriber line interface circuit answering an intraoffice call, a long distance loop connection is established throughout the system by way of the end office between remote station subscribers for charging purposes and the remote station identifies the terminal location of the called circuit. Each remote-station line circuit includes a tone detector.

Abstract: In a TDMA network wherein a central station sends signals towards satellite stations in downward frames (A), each comprising a control time slot (Td0) and speech time slots (Td1 to TdM), and receives signals from one to M satellite stations in upward frames (C) of a like format, the central station checks the number of idle time slots in each of the downward and upward frames. Only when the number exceeds a preselected number, one of the idle time slots is selected as an adjustment time slot. The ordinary number given to the adjustment time slot is transmitted in a number field (Nf) of the downward control time slot. Each satellite station generates a time axis indicative of local time slots (D) with a delay relative to the thereby received downward time slots (B). On adjusting the time axis in a selected satellite station, the station sends a short burst (t.sub.s) in the local time slot indicated by the received number field.

Abstract: In a circuit arrangement of a control station in a radio communication system comprising a plurality of substations, such as a land mobile telephone system, a measuring circuit measures an intensity of electric field in an up control channel to the control station during each quiescent period of signals in the up channel to detect jamming waves. Each quiescent period preferably appears in the up control channel in response to selected control signals of a down control channel to the substations. On detection of the jamming waves, the control channel is switched to a preselected one of speech channels between the control station and substations by switching circuits to use the preselected speech channel as a new control channel.