| 摘要 |
PURPOSE:To prevent a fault of a time division exchange from giving adverse effect onto a frequency multiplex circuit by monitoring a time division multiplex signal outputted from a time division exchange and inhibiting the transmission of the frequency multiplex signal when a fault takes place in the time division exchange. CONSTITUTION:A time division multiplex signal monitoring circuit 23 monitors a time division multiplex signal inputted via a time division multiplex signal line 100 from the time division exchange 10 to send a line circuit signal 25 in response to the state of the time division multiplex signal to a line control circuit 22. The line control circuit 22 sends the frequency multiplex signal 24 of a multiplex conversion circuit 21 to the frequency multiplex line 200. If a fault takes place in the time division exchange 10 and frequency multiplex signal has any error, the output of the multiplex conversion circuit 21 is inhibited. Thus, if any fault takes place in the time division exchange, it is prevented that no adverse effect is given onto the frequency multiplex line. |
