A system for completing an electrical circuit includes first and second base contacts electrically isolated from each other, each having a magnetic portion secured thereto, each magnetic portion having an opposite polarity, and each of said base contacts electrically connected to an electrical lead for transmitting an electrical signal through said base contacts. Left and right buttons serving as first and second function buttons for controlling an object chosen by a pointer appearing on a display, and a third function button for scrolling the screen displayed on the display are provided near one end in the axial direction of the hinge pin between the display unit and a keyboard. It further provides a mark in the header of the video disc to enable random access of a desired frame in the sequence of selected frames.