rearranged and pressed for example a unit key block that has been used for an event for moving a cursor to the left direction is used for the same event even when it is rearranged and changes its position the construction thereof is described below in more detail fig3 is a perspective view illustrating a unit key block of a keypad assembly according to an exemplary embodiment of the present invention referring to fig3 the unit key blocks 210 are discriminated by a protrusion 212 arranged differently the switch unit 232 may fix the unit key blocks 210 by receiving the protrusion 212 the switch unit 232 may include a switch means for generating a signal when pressed the switch means may be one of a dome switch a pressure sensor and the like the switch means is arranged to correspond to protrusions of all unit key blocks for example as illustrated the switch means are arranged in four regions to correspond to four protrusions when the protrusion 212 of the unit key block 210 presses the switch means of the switch unit 232 a signal is generated therefore the switch unit 232 may generate signals from at least one means the main board 230 may detect signals generated from the switch unit 232 to determine a unit key block having a relevant index or protrusion and may generate an event matching with the determined key block in addition the switch unit.