PURPOSE: To communicate with terminals with different interface conditions by receiving the attribute of the other terminal and setting its own interface conditions so as to match for others' if its own interface conditions disagree with others' when a line terminal equipment calls.

CONSTITUTION: With the aid of an interface condition setting part 23, a CPU 20 compares conditions set to the 1st RAM 21 being a storage area for its own interface conditions with conditions in the 2nd RAM 22 being an interface condition storage area of the other party. If there is disagreement, the attribute of the other party is received and selected so that it can be the same as the interface conditions of the other party. The CPU 20 equals the contents in the 1st RAM 21 to those in the 2nd RAM 22 to update attribute contents, and simultaneously modifies a transmission data dissembly/assembly part 24 for periperal circuits required for both connection control processing and for data transmission control processing, a terminal data transmission control part 25 and a terminal call connection control part 26. In order to recognize the modified set contents, the interface condition setting part 23 reads the 2nd RAM 22.