Matsushita Electric Works, Ltd.

Isao Shimada

Koji Ikeda

Yoshiyuki Komoda

Takashi Saeki

Shinji Morino

Kiyotaka Takehara

Yoshihiro Tanigawa

Osamu Akiba

Sadaaki Kondo

Masafumi Morimoto

Teruhito Nakamura

Masashi Sakabe

Terumi Endo

Masayuki Naruo

Kimitake Okugawa

Hitoshi Hukagawa

A device used in a multimedia communication system is formed with a transceiver unit for transmitting and receiving information signal to and from the inside of a room and a base unit adapted to be mounted to a wall of the room to detachably support the transceiver unit. The transceiver unit has a plug surface on which a plug projects, a circular wall projecting on the plug surface to surround the plug, and a guide wall projecting on the plug surface inside the circular wall and around the plug. The base unit comprises a disk member which is provided with a receptacle exposed in a receptacle surface defined on the disk member. The disk member has a diameter slightly smaller than an inner diameter of the circular wall so that the disk member can fit within the circular wall when the transceiver unit is attached to the base. The disk member is formed in the receptacle surface with a guide groove of such a configuration that the guide wall is allowed to be inserted into the guide groove only when the guide wall opposes to the guide groove at a particular angular orientation where the plug comes to be connectable with the receptacle. The device can provide a safe and easy working condition for attaching the transceiver unit to the base unit.

Device for transmitting and receiving information signal in multimedia

An intra-premises communication system enables the use of a preinstalled wired transmission channels, yet allowing a particular communication system to be located at a desired region in the premises. The system comprises an exchange box adapted to be installed in the premises and provided with different interfaces for connection to different networks. A plurality of the wired transmission channels extend from the exchange box and terminate to receptacles which are installed in the premises and have common connectors. A plurality of indoor wireless terminals of different types are provided for use within the premises. A plurality of local transmitter-receivers of different types are provided in correspondence to the types of the wireless terminals. Each of the local transmitter-receivers is detachably and selectively mounted to the common connector of the receptacle for wired communication with one of the networks through the associated transmission channel. The local transmitter-receivers have individual antennas or the like member for wireless communication with at least one of the terminals. The exchange box includes a switch for connecting the transmission channels selectively to particular ones of the interfaces, thereby allocating local transmitter-receivers and the associated terminals to the different networks. The receptacles can be preinstalled in the like fashion as the conventional electrical receptacles so that a desired wireless communication system can be located at a suitable region simply by mounting the local transmitter-receiver of the selected type to the common connector of the receptacle.

Intra-premises communication system

A temperature control system for electric surface heater of piled layers of a heating element across which a commercial AC source current is fed and a thermosensitive electrode opposing the element through thermosensitive element showing negative impedance characteristics with temperature rise. In the system, an AC signal voltage different from the source current is applied between the heating element and the thermosensitive electrode, and excessive variations in the signal voltage responsive to the negative impedance of the thermosensitive element is detected to disconnect or connect the heating element and the source.

Temperature control system for electric surface heater

A time division multiplex transmission system including a central unit and a plurality of terminal units connected through a single pair of bus lines to the central unit. The central unit transmits at least a set of address and control signals sequentially to the respective terminal units and also an electric power required for operating and controlling the respective terminal units at least accompanying the address and control signals. The respective terminal units include a condenser for accumulating the electric power from the central unit so that each terminal unit corresponding to each address signal from the central unit performs any desired operation with the accumulated power and transmits a response signal depending on a result of the operation to the central unit responsive to the control signal.

Time division multiplex transmission system in which electrical power is

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Takarazuka, Japan

Isao Shimada