PURPOSE: To reduce charge for a telephone call and to improve the reliability of guarding by providing a function to vary specified time origination intervals according to specified time origination information from a receiving center, and controlling the specified time origination intervals according to the number of times of the generation of warning.
CONSTITUTION: When an event such as warning occurs to a terminal, the number of a warning receiving center is dialed through the network control part 5 of the terminal. The receiving center receives the incoming signal and sends a signal of prescribed frequency twice successively. A circuit timer part 7 is reset by the 1st answer signal (e) to stop its function. In response to the 2nd data transmission command (f) of prescribed frequency, an information transmission part 8 sends the terminal number, various kinds of guarding information, and an end signal to the receiving center through the network control part 5. After receiving those signals, the receiving center resends one of specified time origination control signals of three prescribed frequencies to the terminal and then resends the normal received signal. When the specified time origination control signals are received respectively, the timer part is preset and intervals of specified time origination are varied.
MURATA YUKIO
SUEYASU YASUNOBU
SOGO KEIBI HOSHO KK