Abstract: A wireless communication system containing at least one transmission apparatus and at least one communication terminal. The transmission apparatus transmits a wireless signal representing a bit sequence containing at least a predetermined number of bit errors, to the communication terminal. The communication terminal receives the wireless signal to regenerate the bit sequence. The communication terminal then examines the bit sequence represented by a received wireless signal to determine whether or not the number of bit errors contained in the bit sequence is equal to or greater than a predetermined number. When it is determined that at least the predetermined number of bit errors are contained in the bit sequence represented by a received wireless signal, the operation of the communication terminal is made inactive.

Abstract: A wireless communication system containing at least one transmission apparatus and at least one communication terminal. The transmission apparatus transmits a wireless signal representing a bit sequence containing at least a predetermined number of bit errors, to the communication terminal. The communication terminal receives the wireless signal to regenerate the bit sequence. The communication terminal then examines the bit sequence represented by a received wireless signal to determine whether or not the number of bit errors contained in the bit sequence is equal to or greater than a predetermined number. When it is determined that at least the predetermined number of bit errors are contained in the bit sequence represented by a received wireless signal, the operation of the communication terminal is made inactive.

Abstract: A radio calling system includes a central control station simultaneously broadcasting a calling signal of an arbitrary pager terminal, and a plurality of radio transmitting stations coupled to the central control station. The plurality of radio transmitting stations simultaneously transmit the calling signal received from the central control station at the same radio frequency. The calling signal transmitted from the radio transmitting stations reach the arbitrary pager terminal and at least a neighboring one of the radio transmitting stations.

Abstract: A control channel monitoring system is for a mobile communication system in which base stations independently control radio zones which are arranged in a cellular array. A mobile station accesses the base station using at least one control channel. Each of the base stations constantly transmits using the control channel in common according to a time division multiple access. A voice signal is transmitted between an arbitrary base station and the mobile station according to the time division multiple access via a speech channel. The control channel monitoring system includes a monitoring part for carrying out a monitoring operation in which a transmission quality of the radio zones is monitored by monitoring the control channel. A selection standard is obtained for the radio zone as the mobile station moves. A silence judging part determines whether the voice signal indicates a silent state based on a level of the voice signal.

Abstract: Prior to the sale of a personal communication terminal, a secret key is generated and stored in the personal communication terminal in accordance with an application made from the manufacturer to the carrier. At this time, the communication between the manufacturer and the carrier is performed in the form of secret communication with a signature that conforms to a public key system. After the sale, an identification number encrypted with the same key as the secret key is transmitted to the personal communication terminal in accordance with an application made from the user to the carrier. Using the stored secret key, the personal communication terminal decrypts the received identification number for storage therein.

Abstract: A line control method is applied to a mobile communication system in which a mobile station communicates with one of a plurality of base stations which are installed within the same zone via a speech channel of the one base station, where the base stations have a common control channel.

Abstract: An in-house paging system includes a call controller connected to an in-house switching unit for providing an interfacing process in response to a call request from an extension terminal. A plurality of transmitting units are connected to the call controller through a signal line and a power source line. A pager terminal is provided for notifying a maintenance staff of a call signal from a transmitting unit on receipt of the signal. The transmitting unit comprises a detecting unit for detecting whether or not an abnormal condition arises in a signal line or a power source line to a call controller and a signal/power-source line abnormal signal transmitting unit for transmitting abnormal condition information to the pager terminal when the detecting unit detects an abnormal condition in the signal line or the power source line. A battery as a backup power supply unit is used in case of power disconnection.