PURPOSE: To effectively use a one operation key abbreviated dialing number by storing plural dialing numbers for as single one operation abbreviation dialing number and selecting a dial number based on a class connection of an external terminal.

CONSTITUTION: A dial data storage section 109 stores a telephone number, a facsimile number and a data terminal number with respect to one operation abbreviation dialing number. Then depending on the presence of connection of an external terminal, a channel switching section 107 is switched to the position of receivers 101, 102 or an external terminal equipment connection section 103, and when the one operation abbreviation dialing number indicating a transmission destination is depressed, a control section 108 discriminates the presence of the connection of the external terminal equipment and discriminates a class of the terminal equipment when being connected. Then corresponding dial data are retrieved and extracted depending on the class of the terminal class number received from a terminal class discrimination section 105. Thus, the same transmission destination is designated by the same destination number independently of the presence of the external terminal equipment in use and its type.