PURPOSE: To make data transfer possible for any outputting device by adding an interface of different kind from a printer interface that transfers output data stored temporarily in a buffer, and making either interface effective through a switch.

CONSTITUTION: A buffer 122 that stores data outputted from a data processing device 11 temporarily is incorporated in a printer buffer unit 12. The data are supplied to a printer unit 13 through an incorporated switch 126 and a centronics interface for output 15, and on the other hand, supplied to other outputting device through an RS 232C interface 16. The switch 126 designates whether the data stored temporarily in the buffer 122 are to be supplied to the centronics interface 15 or to be supplied to the RS 232C interface 16.