The present invention relates to a mobile terminal, which can sense a touch input in which a touch screen is tapped while the touch screen is in an inactivated state, and a communication system thereof, and provides a mobile terminal comprising: a wireless communication unit for transmitting and receiving data to/from an external terminal positioned within a predetermined distance; a touch screen converted, to another state, from one of an activated state in which the light is on and an inactivated state in which the light is off, and formed so as to sense a touch input; and a control unit for sensing, by using the touch screen, a plurality of touch inputs to be applied to the touch screen, which is in the inactivated state, unlocking a locking state when the sensed touch inputs are matched with a preset pattern, converting the touch screen, which is in the inactivated state, into the activated state, and transmitting, to the external terminal, an unlocking command formed so as to unlock the locking state of the external terminal, wherein the external terminal unlocks the locking state by responding to the unlocking command, and displays preset screen information on a display unit provided in the external terminal.