| 摘要 |
PURPOSE:To prevent the degradation of exchange connection service by allowing a terminal line controller being a reception terminal device to check the normality of line control information added with a normality confirming signal and making the reception line control information ineffective during a fault. CONSTITUTION:The line control information S2 is read periodically from a storage memory 3, an insertion circuit 5 adds a normality confirming signal S3 generated by a normality confirming signal generating circuit 4 and transmits it to a terminal line controller 6 through a circuit control information transfer line 12. The normality of the information S4 in the circuit 12 is checked by a normality confirming signal check circuit 7. When the result is normal, the information S4 from the line 12 is written in a storage memory 8 of the line control information and the content is revised. On the other hand, a write signal S5 from the circuit 9 is not outputted during a fault and the content of the memory 8 is the same as being written before the fault. The information of the memory 8 is read periodically, transmitted to a terminal circuit 11 via a multiplex separation circuit 10 and the line is controlled. |
