A digital telecommunications system, a method of managing a communications network in such a system and a program product for managing audio transmission in a digital communications system. The joystick is aligned with a neutral position contact portion of the PCB when the joystick is in a neutral position. A parallax barrier is placed in front of the image display unit, and has light interception portions and light transmission portions alternately and repeatedly arranged in a horizontal direction of the image display unit to separate left-eye image light beams from the first pixels and right-eye image light beams from the second pixels in directions of left and right eyes of a viewer. The primary processor then initiates updating its firmware with the corresponding updated set.