PURPOSE: To monitor the call processing and general operating information of an exchange at the same time by dialing a specific number in a terminal to connect it to a sound source and a selecting device through an automatic answering trunk.

CONSTITUTION: The trouble information 17, 18, and 19 of a monitor and test frame 16 correspond to an important fault, a light fault, and a door alarm respectively. When detecting the important from a controller 13, the test frame 16 generates information 17. When receiving fault information, a sound source and selecting device 17 selects a sound source corresponding to information 17 to prepare for transmission. Meanwhile, when a maintenance person dials a specific number by a telephone set 11, it is connected to an automatic answering trunk 14. Consequently, the sound corresponding to the information 17 is transmitted to the telephone set 11 through the trunk 14. The maintenance person hears the sound to discriminate the classification of the sound source and grasps the operating information of the exchange.