PURPOSE: To simply test a terminal equipment to monitor the terminal equipment by inputting a state input and an alarm input to the terminal equipment so as to allow the terminal equipment to make transmission to a center through a line in terms of usual message with respect to the alarm system, comparing the message with test information in a test table, adding a test message to the received message, storing the result and suppressing raise of alarm when the comparison indicates a range so as to avoid confirmation by a center supervisor as to the presence of test and trouble of description of the test state to the message and mis-description.

CONSTITUTION: As to a message received from a terminal equipment 2 being an object of supervision through a line, when a test state presence/absence flag 13 in a range 12 of a test table 11 is discriminated to be 'presence', a test state is added to the message and the result is stored and an alarm output according to the message is suppressed. On the other hand, when the absence is discriminated, the message is stored and an alarm output is made according to the message by mean of a test discrimination processing section 14, which is provided to the center 1.