| 摘要 |
PURPOSE:To attain various controls at the transmission side of a carrier device via a carrier device at the reception side, by generating a pattern with an intermittent monitor current at the transmission side of monitor current and discriminating the pattern at the reception side to execute corresponding controls. CONSTITUTION:A signal such as voice is modulated at modulators 10-1-10-n, superimposed on a line monitor current LINE.PIL at a transmission amplifier 1, and transmitted to a radio relay station via a radio equipment 3 and an antenna 4, and for controlling the radio relay station from the transmission side, the monitor current LINE.PIL is intermitted with a pattern in response to the content of control with a pattern generator 15. At the radio relay station, the signal such as voice is demodulated at demodulators 11-1-11-n via a radio equipment 3' and an amplifier 2'. Further, a monitor current detection and alarm circuit 5 detects the monitor current LINE.PIL at the same time and the intermittent signal with the pattern is transmitted to a pattern discrimination and control circuit 12, where the corresponding control such as the discrimination of the pattern and control of switching devices 13, 14 can be done. |
