A multifunction device previously stores a line connection condition of when a line interface received caller ID information in an EEPROM, and determines that a line with an exchange is connected based on a first ringing signal or a second ringing signal. When it is determined based on the first ringing signal that a line connection is a first type of connection, the line is connected according to the line connection condition. On the other hand, when it is determined based on the second ring signal that a line connection is a second type of connection, the line is connected using a line connection condition, which is adjusted by an adjustment device at the time of determination.