To provide a communication interface which can automatically set communication ID of itself when neighboring pachinko game machines or data displays of the pachinko game machines are connected.

In the connected communication interfaces A-C, connection numbers of status 23L of main control part interface 2L in the left side are in an ascending order 1, 2, 3 from the left side end. Connection numbers of status 23R of main control part interface 2R in the right side are in an ascending order 1, 2, 3 from the right side end. Accordingly, the total number of connected communication interfaces A-C is detected, simultaneously respective own position from the left side end and the right end side in the connection mode can be automatically detected, and respective own connection number (communication ID) by interfaces A-C can be automatically detected. The pachinko game machine or the data display of the pachinko game machine on which the communication interface is mounted can be controlled by connecting and interlinking with a communication line.