| 摘要 |
PURPOSE:To attain data communication at an optional time by providing a controlling transmission line transmitting only a control data to transmit the control data, thereby activating a communication line. CONSTITUTION:When a line state 7 between devices 1 and 2 is activated, the line between the devices 1, 2 is connected and a serial data is transmitted or received via a data transmission line 4 and a data reception line 5. When a transmission request line 6 between devices 3, 1 is activated during data transmission/ reception between the devices 1, 2, the transmission request is issured from the control section 3b of the device 3 to the control section 1b of the device 1, and the device 1 responds to the transmission enable, the data transmission/reception between the devices 1, 2 is interrupted and the line state line 7 is inactivated. Then the line between the devices 1, 3 is connected and the data is transmitted/ received between the devices 1 and 3. |
