CLOCK PULSE SUPPLY SYSTEM FOR DATA TRANSMISSION AND RECEPTION OF COMMUNICATION CONTROLLER

摘要

PURPOSE:To prevent the mixed presence of communication errors by providing a circuit identifying whether a clock pulse supplied from the outside of a line adaptor or the like or a clock pulse generated in the inside of a line connection section is used as a clock pulse required for the data transmission/reception of the line connection section. CONSTITUTION:A pin number #M of a connector 70 is not connected to a pin number #N of the connector 70 A line connection cable type identification section 60 investigates a signal level of the pin having the number #N of the connector 70 to detect a logical OFF state and recognizes that the type of cable to be connected is not a line bustback cable 51 but a cable 50 connected to a line adaptor. Then the line connection cable type identification section 60 commands that the clock pulse to be used by a transmission/reception control section 20 is a clock pulse sent from the line adaptor to the transmission/ reception control section 20, the transmission/reception control section 20 uses the clock pulse of the line adaptor 10 to start the transmission/reception.