PURPOSE: To efficiently transmit data of a mixed mode.

CONSTITUTION: In a repeater station capacity deciding part 15 and a terminal station capacity deciding part 16, whether a repeater station or a terminal station has the capacity for receiving and processing character data or not, respectively is decided. The decision is based on the other station information registered in advance. In the case the repeater station has the receiving capacity, a processing of a document is entrusted to a receiving capacity decision of the terminal station by the repeater station. Also, in the case the repeater station has no receiving capacity, in accordance with whether the terminal station has the receiving capacity or not, a document obtained by converting the character data part to image data is sent out in the case it is necessary. In the case the repeater station has not receiving capacity, and also, a station having the receiving capacity and a station being not so are mixed in the terminal station, in accordance with a decision of an instructing station by its mixed state, a document obtained by converting the character data part to image data is sent out in the case it is necessary.