Abstract: In a cordless key telephone system, access units are located in groups corresponding to service areas for broadcasting radio signals on a control channel or on an assigned speech channel to cordless stations. A main controller selects one of the access units for each service area in response to an incoming call from the switched telephone network and sends a first alert signal to the selected access units to cause them to broadcast a recurrent sequence of second alert signals containing the identifiers of standby cordless stations. The second alert signal is received by each standby cordless station and an ACK signal is transmitted if the received signal contains its identifier. The ACK signal is copied by each access unit for transmission to the main controller, whereupon it returns a proceed-to-assign signal if the number of the received copies of the ACK signals is equal to the number of all standby stations.

Abstract: In a method and apparatus for controlling a radio telephone system, a speech channel is established between the slave radio set of a plurality of radio telephone sets and a radio set of a base unit. An intercom switch for selecting intercom performances is provided for respective radio telephone sets. The slave radio sets of the radio telephone sets are turned OFF when the intercom switch is OFF, and transmitters of the slave radio sets of the radio telephone sets are turned ON. Consequently the connection between a wired telephone channel and the plurality of radio telephone sets can be controlled with a single base unit connected to the wired telephone channel.

Abstract: A cordless telephone system comprises a radio telephone set and a connection unit connected to a wire telephone circuit and also connected to the radio telephone set through a radio communication circuit, for interconnection control between the wire telephone circuit and the radio telephone set. When the wire telephone circuit is put in an unusable state or a signal on the radio communication circuit is put in an unreceivable state, the connection unit transmits a disconnecting signal to the wireless telephone set to forcibly cut off the radio communication circuit.

Abstract: A cordless telephone having a base unit and a plurality of radio telephone sets. The base unit delivers a ringing signal from a telephone line to a radio telephone set which is in telephone communication with a remote subscriber coupled to the telephone network, and a receiving radio telephone set in accordance with a request for transfer by the transferring radio telephone set. If the receiving radio telephone set responds to the ringing signal and goes off-hook, the telephone communication is transferred to the receiving radio telephone set from the transferring radio telephone set. If the receiving radio telephone set does not respond or does not go off-hook, the transferring radio telephone set responds to the ringing signal and goes off-hook to carry on the telephone communication.

Abstract: A method and apparatus for controlling a radio telephone system wherein a speech channel is established between one radio telephone handset out of a plurality of radio telephone handsets and a base unit. An interphone switch for selecting intercom communication is provided for respective radio telephone handsets. The transmitters of the radio telephone handsets are turned OFF when the intercom switch is OFF, and transmitters of the radio telephone handsets are turned ON when the intercom switch is ON. Consequently the connection between a wired telephone channel and the plurality of radio telephone handsets can be controlled with a single base unit connected to the wired telephone channel.

Abstract: A radio telephone system includes a base station connected to a telephone exchanger and a plurality of mobile stations connected to the base station through a radio channel including a control channel and communication channels. The base station includes a transmitter/receiver, a receiver, and a controller. In a stand-by mode, the controller sets a channel of the transmitter/receiver to the control channel to receive a calling signal from each mobile station and sets a channel of the receiver to a given communication channel to monitor vacancy of the communication channels.

Abstract: For use in a mobile radio telephone network including radio telephone sets movable in an area divided into a predetermined number of zones, a communication control system includes a searching arrangement (25, 33) for searching one (15') of radio communication devices of the network as a searched communication device that is assigned to a present one of the zones into which a specific one (11') of the radio telephone sets has moved from a previous one of the zones. For operation of the searching arrangement, a communicating arrangement (22, 25, 32) of the system sends a call signal to a specific one of the radio communication devices that is assigned to the previous zone to transmit the call signal to the specific telephone set and receives a response signal transmitted from the specific telephone set if the specific telephone set were in the previous zone.

Abstract: A method and apparatus for controlling a radio telephone system of the type wherein a connection between a wired telephone channel and a plurality of radio telephone handsets is controlled by a single base station connected to the wired telephone channel, a ring signal through the wired telephone channel is detected, a paging signal is sent to the radio telephone handsets from the base station when the ring signal is detected and a paging response signal is sent to the base station from the radio telephone handset in response to the paging signal.

Abstract: Where a carrier wave is received from a called radio telephone set and where the identification signal of the radio telephone set coincides with a preassigned identification signal, transmission of a paging signal from a base unit is stopped. Even when the identification signals do not coincide with each other, the paging signal is sent continuously over a definite interval. Communication is established only when the signal from a handset to the base station has a predetermined strength and a proper I.D.

Abstract: A method and an apparatus are disclosed for controlling a radio telephone system comprising a single master apparatus connected to a subscriber line and a plurality of radio telephone sets connected to the master apparatus by way of radio channel. When a call origination operation is made by one of the radio telephone sets, a call originating signal is sent to the master apparatus from the call originating radio telephone set. In response to the call originating signal, the master apparatus switches its radio channel to an idle speech channel, and sends a channel designating signal representing the idle speech channel to the plurality of radio telephone sets including the call originating radio telephone set so as to switch the radio channels of the radio telephone sets which have received the channel designating signal to the idle speech channel.

Abstract: A portable unit that may be called from a base station through a radio control channel by a succession of terminating call signals that is sent through the control channel from the base station to the portable unit for a first or restricted time duration (T.sub.1), selected in consideration of a battery saving period of a battery saving operation carried out in the portable unit. Within the battery saving period, the portable unit is put into transient active and inactive states during a first time interval and a second time interval, respectively. Selection is made so that the first time duration is longer than the second time interval to receive at least one of the terminating call signals within the first time duration in the portable unit. The base station monitors an acknowledgement signal for a second time duration (T.sub.2) after the lapse of the first time duration and interrupts the control channel when the acknowledgement signal is not received within the first and the second time durations.

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 portable unit that may be called from a base station through a radio control channel by a succession of terminating call signals that is sent through the control channel from the base station to the portable unit for a first or restricted time duration (T.sub.1), selected in consideration of a battery saving period of a battery saving operation carried out in the portable unit. Within the battery saving period, the portable unit is put into transient active and inactive states during a first time interval and a second time interval, respectively. Selection is made so that the first time duration is longer than the second time interval to receive at least one of the terminating call signals within the first time duration in the portable unit. The base station monitors an acknowledgement signal for a second time duration (T.sub.2) after the lapse of the first time duration and interrupts the control channel when the acknowledgement signal is not received within the first and the second time durations.

Abstract: According to the invention, there is provided a cordless telephone apparatus having: a fixed unit and a portable unit, each having a control device for channel scanning to determine whether or not each of a plurality of channels is engaged, the portable unit being battery charged when it is attached to the fixed unit; a connecting line for transmitting and receiving signals between the two control devices when the portable unit is attached to the fixed unit; and a system for synchronizing the channel scanning processes of the two control devices through the connecting line.

Abstract: A mobile radio communication system having a plurality of fixed stations respectively connected to a plurality of subscriber's lines extending from a telephone exchange, and a plurality of mobile stations linked with the fixed stations through radio channels. Each of the mobile stations effect speech via one of the fixed stations. The system comprises means provided for each fixed station for transmitting rate charging information from the telephone exchange to a mobile station under speech, and rate collecting means provided for each mobile station and being responsive to the rate charging information to vary its content.

Abstract: A paging or like radio communication receiver is disclosed having a crystal oscillator circuit which is connected directly with a power source and is thus held continuously in oscillation at its preset level of frequency irrespective of whether the power supply ON/OFF switch is closed or not. The novel arrangement enables the receiver to produce a normal quality call sound whenever the swtich is closed and the proper signal is received, even at the instant of its start, and substantially extends the service life of the battery.

Abstract: A digital paging communication system including a transmitter and a plurality of receivers is disclosed. The transmitter generates a preamble digital signal, a calling digital signal and an end mark digital signal in a predetermined sequence. Each receiver demodulates a received signal into the preamble digital signal, calling digital signal and end mark digital signal. These signals are separately detected in synchronism with a recovered clock signal. Power is supplied to the radio frequency, intermediate frequency and demodulator sections of the receiver intermittently until such time as the calling signal of the receiver is detected, after which power is supplied continuously until an end mark signal is detected. The intermittent operation is a battery saving feature.