PURPOSE: To attain the reoutput of the received data and to avoid the delay of response and the deterioration of the processing ability by storing the received data in a reception buffer of an external memory for a fixed period based on the reception buffer control information and also storing the data for a fixed period even after output to an output device.

CONSTITUTION: A deciding means 2 decides whether the data 1-1 received from a host 1 should be stored or not in an external memory 3 based on the reception buffer control information 1-2. The means 2, 4 and 6 function to store the accumulated data 1-1 for a fixed period and to make an operator instruct the reoutput of the data 1-1 in off-line to an output device 5 based on a list of received data within said fixed period. Thus it is possible to output again even the information that is outputted once as necessary within a fixed period. As a result, the retransmission request is omitted to the host 1 for reduction of the load. Then a copying function is also secured even in case many copies are required for information.