PURPOSE: To understand the detailed contents such ad the emergency state even at an informing destination by rereading the signal input from a terminal to detect the condition of connecting equipment, sending it through a telephone line as digital data and printing the detailed information such as the place of abnormarity, etc., to a printer.

CONSTITUTION: To a supervising board C, plural terminals 9 are connected from a multiple transmitting signal converting part 3 through a multiple transmit ting line. The terminals 9 output the condition change, etc., of the connecting equipment and have an address collating function. The abnormal signal from the terminals 9 is received by a multiple transmitting signal converting part 3, re-read through a bus line B by a re-reading table 2, sent through a telephone line 6 to a receiving side telephone set 7 from a transmitting side telephone set 5 through an RS232C as a digital signal at a serial output part 4 and again, printed and outputted through the RS232C to a printer 8. After the abnormal signal as a representative is received at the informing destination, the hourly printing-contents of the printer are confirmed, and the shifting of the abnormal contents can be recognized with a high system.