Fujitsu Corporation

Takuro Oguchi

Masaru Asahara

Shunroku Sasaki

Kunio Watanabe

Minoru Maruyama

Zenichi Ohsawa

Hajime Masuda

Shinichi Murai

An information guiding system is composed of cordless portable terminal units which are to be carried by visitors of a museum, radio base stations, an exchange, and an audio response equipment. A portable terminal unit transmits a service number for guiding to a radio base station so as to request the radio base station to set a call to the audio response equipment, and the radio base station transmits the call setting request to the exchange, which sets a speech path to the audio response equipment in answer to the call setting request. The portable terminal unit then transmits information (the number of an exhibit, the language and the information depth) designating an audio file via the radio base station, the exchange and the speech path. The audio response equipment takes out the information about the exhibit on the basis of the information designating the audio file, converts the information into audible sound signals, transmits the audible sound signals to the speech path, and transmits the signal to the portable terminal unit which has called, via the exchange and the radio base station.

Information guiding system and method of preventing borrower of portable

A mobile communication system includes an exchange, a plurality of radio base stations coupled to the exchange, and a plurality of mobile stations. The exchange includes a device for obtaining receivable periods of the mobile stations, which are continuously maintained in a call receivable state during the receivable periods, a device for determining whether the mobile stations are busy and a decision device which sequentially sends call signals to the mobile stations to determine whether or not each of the stations responds to a call signal. The results of determination by the decision device are recorded in a recording device.

Mobile communication system

A radio communication adapter is used in a mobile communication system including a first mobile communication network, first mobile stations registered in the first mobile communication network, a second mobile communication network connected to the first mobile communication network, and second mobile stations registered in the second mobile communication network. The radio communication adapter is attached to one of the second mobile stations. The radio communication adapter includes a radio communicating part for communicating, via a radio channel, with the first mobile stations located outside a first service area of the first mobile communication network, and a requesting part for requesting that first identification data of the first mobile stations located outside the first service area is registered, in connection with the second mobile stations, in the first mobile communication network via the above-mentioned one of the second mobile stations and the second mobile communication network.

Radio communication adapter connected to mobile station and mobile

A portable telephone system includes a first telephone network including a terminal station, a first telephone set connected to the first telephone network via the terminal station, a second telephone network including a communication center which is connected to the first telephone network at a connection point, and at least one second telephone set registered in the communication center and connected to the first telephone network via the terminal station. The second telephone set is a portable telephone set having a base station part and a portable station. The communication center includes a first part for sending a line hold signal to the first telephone set via the first telephone network when a call to the portable station of the second telephone set is received via the first telephone network, and a second part for sending control information to the base station part of the second telephone set, where the control information includes a notification that a call is made to the portable station of the second telephone set from the first telephone set and a telephone number of the first telephone set. The base station part of the second telephone set includes a third part for dialing the telephone number of the first telephone set in response to the control information received from the communication center, so that a service connection is made, after the third means dials the telephone number of the first telephone set, between the first and second telephone sets via the terminal station of the first telephone network.

Portable telephone system having selectable bypass line

A temperature compensating voltage generator circuit for compensating temperature characteristics of an electric circuit whose electrical characteristic varies in accordance with the change of the ambient temperature and whose electrical characteristic can be changed or controlled by a control voltage. The temperature compensating voltage generator circuit comprising a plurality of temperature sensitive resistor circuits, a plurality of diode circuits and one or more resistor circuits. A temperature compensating voltage from the temperature compensating voltage generator circuit being independently adjustable at each predetermined temperature.

Temperature compensating voltage generator circuit

The present invention discloses a straight-through-repeater which relays a frequency-modulated microwave signal. The straight-through-repeater is basically comprised of a phase-locked loop circuit located between receiving and transmitting antennas of the repeater. The phase-locked loop circuit has a demodulating capability for reproducing a baseband signal, a power amplifying capability, a very narrow filtering capability, an automatic gain controlling capability and an amplitude limiting capability. The repeater is further comprised of a means for suppressing a step-out of synchronism occurring in the phase-locked loop circuit.

Straight-through-repeater

The present invention discloses an FM microwave radio frequency repeater using the straight-through system for relaying signals of a plurality of channels having different carrier frequencies, each of the channels including an auxiliary channel. The system according to the invention is characterized in that the auxiliary channel has the signals thereof demodulated through frequency discrimination of a difference frequency signal obtained by mixing together two received microwaves.

Growing community of inventors

Kawasaki, Japan

Takuro Oguchi