| 摘要 |
976,462. Electric selective signalling systems. SIEMENS-SCHUCKERTWERKE A. G. Nov. 18, 1963 [Nov. 16, 1962], No. 45492/63. Heading G4H. A field station system is characterized in that the central station and each field station includes a cathode ray tube which distributes received data and produces clock pulses for transmitting data. As described all the cathode ray tubes are synchronized by a source pf clock pulses 14 and each complete scan is divided into an upper-half, or transmit cycle, during which the central station G can transmit data to the field stations, and a lowerhalf, or receive cycle, during which the central station can receive data from the field stations. During a transmit cycle the central station cathode ray tube applies pulses sequentially to a number of leads, one for each of a number of switches 11, each one of which has a corresponding switch in one of the field stations. As the switches are scanned each one that is closed causes a pulse to be applied to the transmission line which pulse brightens the cathode ray tube beams in all the field stations. At the field station which contains the switch corresponding to the central station switch which caused the beam to brighten a connection will exist so that in response to the brightened beam a device 30 is tripped to actuate the switch to the desired position. During a receive cycle switches at the field stations are scanned by pulses from their cathode ray tubes, any closed switch causing a pulse to be transmitted to brighten the central station cathode ray tube beam which, via a device 10, controls indicators so that the central station supervisor knows the positions of the switches in the field stations. The pulses from the cathode ray tubes can be produced either by an array of photo-electric cells adjacent to the face of the tube or by target electrodes in the tube. |
