According to an embodiment, a method for controlling a portable device connected to an earphone having a coil includes detecting removal of one of left and right units of the earphone worn by a user, generating an electromagnetic pattern corresponding to an Identifier(ID) of the portable device at the removed unit of the earphone, and receiving data from the external device in correspondence with the ID of the portable device. According to an embodiment, a method for controlling a display device includes displaying a Graphic User Interface on a display unit, sensing an earphone within a detection area of the display unit, sensing an electromagnetic pattern of the earphone within a detection area of the display unit, acquiring an ID of an external device connected to the earphone from the sensed electromagnetic pattern, and transmitting data to the external device identified by the acquired ID of the external device.