Abstract: A slave station at an end location of a transmission route is responsive to a polling signal issued from a master station such that if there exist data to be sent to the master station, the slave station transmits a code with a "busy" token and specifying the data to a slave station at the next upper location; and if there do not exist data to be sent to the master station, the slave station transmits a "free" token to the slave station at the next upper location. When the slave station at the upper location receives the "busy" token from the station at the lower location, the slave station at the upper location relays the entire codes receives.

Abstract: A remote monitoring and controlling system in which time information from a secondary clock in each slave station is transmitted in coded signal form to a master station in response to a time inquiry command issued from the master station. The transmitted time information and the time information of the primary clock of the master station are compared in the master station by taking into account the length of the coded signal and a transmission delay time from the corresponding slave station. The difference found by the comparison is temporarily stored in memory as time correction data to be used to correct the time information of the respective slave stations.

Abstract: The inventive master station apparatus for a remote supervisory control system makes poke points for selecting remote stations displayed on a video display (3) by an output control circuit (24), so that, when an operator touches one of the poke points on a touch panel (4), a CPU (21) makes the pattern and the current status of a monitored/controlled device of the corresponding remote station and a poke point for a control command displayed. When the poke point for the control command is touched, the CPU (21) transmits a control command to the monitored/controlled device of the corresponding one of remote stations (11, 12, . . . , 1n) through a line interface (5). When control of the corresponding device is executed, the remote station transmits a signal indicating the operation thereof to the master station apparatus (1).

Abstract: A master station in a supervisory control system comprises a console (3) having a card reader (5) and control switches (9, 11, 13), a card (7) being inserted into the card reader. Information specifying a substation (271-27n) and a device (D11-Dnm) included in the substation is recorded in machine and human readable form on the card. A signal from the card reader is applied to an output control (23) through an input control (17), the output control reading the contents of a status memory (21) and a pattern memory (25) associated with the substation and device specified by the card, and providing a pattern display on a video display (1) based on the read information. The display of the selected device is flashed on the video display. An operator's actuation of the control switch causes the input control to send the control command to a line interface (19), and the line interface transmits the control command to a substation containing the selected device.

Abstract: A method for synchronizing the times of a master clock provided in the master station and slave clocks provided in the slave stations in a data transmission and receiving system consisting of the master station as a data transmission control station and slave station and/or stations for two-way data transmission. An encoded time survey command including master clock time is transmitted from the master station to each slave station. This is followed by an encoded response from each slave station which includes the slave clock time, from which the transmission delay to and from the slave station is determined along with the time difference between master and slave clocks. Time correction data is then transmitted to correct the time of the slave station clock.

Abstract: Digital equipment such as an electronic computer comprises a memory unit, an operation unit and a processing unit. In the digital equipment, a short-time service interruption compensation means in compact and simple constitution is installed within a power conversion circuit, and a timer circuit to halt each of the equipment in case of service interruption for a long time is provided as a runaway preventing safety means for the equipment. A power conversion device of the digital equipment is composed of a rectifier circuit which rectifies the commercial power source voltage, a battery as a service interruption compensation means which performs floating charge of the rectifier circuit output and discharges the charged DC power source so as to treat service interruption of the commercial power source, and a DC to DC conversion circuit which converts DC current from the rectifier circuit at normal state or from the battery during service interruption in DC-DC conversion.

Abstract: A signal communication system provided in a board device has a signal input/output terminal board having a plurality of input/output terminals. When a signal is communicated between two board devices, some of the input/output terminals serve as an input signal terminal and the remainder as an output signal terminal in accordance with the manual selection thereof.

Abstract: A security system including a television camera for taking a scene of a trespass upon a predetermined region at a site to be monitored, a video recorder for recording the image of the scene taken by the television camera, and a sensor for sensing a trespass and outputting a signal for starting the television camera and the video recorder. The signal output from the sensor for sensing a trespass and the outputs of a plurality of other sensors sensing other conditions at the site to be monitored are transmitted to a monitoring site remote from the site to be monitored for display at the monitoring site.