| 摘要 |
PURPOSE:To make the correspondence to a terminal device suitable, and to make the bracketing of failures efficient, by discriminating the presence of connection of the terminal device to a terminator at a master station through the use of a specific pattern. CONSTITUTION:A specific pattern X is inserted to a specific time slot on a transmission frame at a master station 1, a transmission signal is transmitted to each terminal device 3 via each terminator 2 and a transmission line 4 at all times, a device 3 inserts a specific pattern Y to the same frame pattern as the signal from the master station 1 and transmits it to the master station 1. The device 2 has a switching circuit 5, transmits the transmission signal to the master station 1 at the connection of the device 3, transmits a signal from the master station to the device 3 and returns the signal from the master station to the master station via the circuit 5 at the non-connection of the device 3. The master station 1 discriminates the connection of the device 3 through the reception of patterns X,Y for specified correspondence. |
