| 摘要 |
PURPOSE:To attain ease of data recovery of a terminal equipment by transmitting sequentially a standard time signal and a polling signal through a communication line from a central device to plural equipments, returning a timer data and a time signal from the terminal equipment and correcting the time. CONSTITUTION:The polling signal and the standard time signal are transmitted from a device main body 11 and a standard clock 12 of a central device 10 while an address of terminal equiments 20A, 20B... is added and modulated by an MODEM13 to a communication line 30. A terminal equipment 20i etecting the own address transmits a time signal of the clock provided to the terminal equipment and the number of pulses proportional to the value measured by the terminal equipment until that point of time to the central device 10. The central device 10 measures the pulse from the terminal equipment 20i, surveys the load and when the time signal is shifted from the standard time by a prescribed value or over, an alarm is raised and a maintenance personnel visits to the place for the repair of the terminal equipment 20i. Thus, the load is surveyed rationally. This system is suitable for metering job such as water supply or gas supply. |
