| 摘要 |
PURPOSE:To relieve the load of a common controller by sampling a scanning signal of each line from a time division multiplex scanning signal and inputting only changed information of the result of sampling to the common controller. CONSTITUTION:A scanning signal of plural subscriber terminal devices 10-1m is multiplexed respectively by time division multiplex circuits A-M of subscriber terminal devices 20-2m via supervising points a-m and inputted to a scanning signal change detector 4 from a scanning signal route 3 as a time division multiplex scanning signal. The scanning signal change detector 4 controls the time division multiplex scanning signal of a period T from the common controller 6 via sampling control route 7. The detection of change is conducted by the scanning signal change detector 4 based on the result of sampling, and after the change information is stored in a first-in first-out device 5, the information is read by the common controller 6. |
