PURPOSE: To save the storage capacity of a communication line monitoring equipment, to facilitate a processing afrer storage and to save manpower during an operation by permitting a terminal and the communication line monitoring equipment to execute the operation by means of linking.

CONSTITUTION: The terminal announces the start and end of a series of telegraphic message by a telegraphic message transmission start announcing means 3 and a telegraphic message device ending means 4. In the communication line monitoring equipment, a storage means 10 starts the storage of the deceived telegraphic message by the announce of telegraphic message transmission start from the terminal and an information recorder 11 records the storage contents of the storage means 10 in an information recording medium by the announce of the telegraphic message transmission end from the terminal. When recording from the information recorder to the information recording medium is ended, a recording end announcing means 12 announces recording end to the above terminal. The terminal transmits the next series of telegraphic message after announcing telegraphic message transmission start by the announce of recording end.