| 摘要 |
PURPOSE:To safely control the whole of a network with the use information of a PAMA line with a master station by providing a demodulator for PAMA and a synthesizer to be able to select the full frequency of a PAMA communication channel at a receiving part in a master station transmitter-receiver. CONSTITUTION:In a transmitter-receiver 10A of a master station 2A, a demodulator 32 for permanent assignment multiple access (PAMA) and a synthesizer 34 are provided and in a control device 9A, a synthesizer control part 39 is provided. The master station 2A selects and receives the full frequency of a PAMA line, judges the use condition of the PAMA line according to the presence of the carrier of the communication line, and when the carrier is prevent, the signal from the slave station 1A is received by the carrier and demodulation data 321 are outputted. Thus, even when the PAMA communication is executed at the section of the slave station 1A, the master station can safely control the whole of the network. |
