| 摘要 |
PURPOSE:To eliminate the need for consciousness of polarity of a transmission line when a digital code converter of a receiving device is installed, by controlling and fixing said digital code converter so that a digital signal is coincident with a fixed digital code at the initiation of communication. CONSTITUTION:A control circuit 12 of a transmitting device 1 supplies a fixed digital code to a multi-value coder 13 via a data selector based on a control signal 15 showing the initiation of command. The coder 13 converts the digital code into a multi-value code and transmits it to a transmission line 3 via a transmitting circuit 14. The burst signal which is fed to a receiving device 2 via a receiving circuit 24 and then converted into a multi-value signal is supplied to a multi-value decoder 23. The output 28 of the decoder 23 is varied furthermore by a digital code converter 21 and then delivered. A control circuit 22 compares the output 26 of the converter 21 with a fixed digital code on the basis of a control signal 25 showing the initiation of communication and controls the converter 21 with a control output 27 so as to obtain the coincidence for said comparison. Hereafter, this control is fixed. |
