| 摘要 |
PROBLEM TO BE SOLVED: To detect a transmission line fault, even if a non-transparent digital network exists between multiplex devices. SOLUTION: A multiplexer consists of: sound channel boards 7a and 7b which encode a sound signal, perform decoding to the sound signal, and level- convert a signaling signal; a multiplex separation/conversion board 8 which generates and separates an information transmission signal obtained by multiplexing the signaling signal and an outer contact point information, detects a transmission line fault from the received information transmission signal, multiplex-converts the encoded signals of 23 channels and the information transmission signal and separates and converts the multiplex signal into the encoded signal of the 23 channels and the information transmission signal; an interface board 9 which code-converts the multiplex signal into a prescribed transmission line signal, outputs it, code-converts the inputted transmission line signal, outputs it, extracts a received clock signal and establishes synchronism; a clock board 10 which generates the clock signal required in the device; and an alarm board 11 which outputs an alarm signal to the outside. |
