Abstract: A keyboard with a simplified structure, which is connected to a main computer having a microcomputer in which a key map is stored therein and which generates first and second scanning signals via respective scan input lines and receives first or second scanning codes via respective scan output lines upon a key on the keyboard being operated. The keyboard includes first and second keyboard frames separated from each other, and a first key matrix assigned to the first keyboard frame and disposed adjacent thereto, for generating the first scanning code in response to the first scanning signal, and a second key matrix assigned to the second keyboard frame and disposed adjacent thereto, for generating the second scanning code in response to the second scanning signal.

Abstract: An audio expansion system for enhancing sound reproduction function of the portable computer includes a digital audio processing chip, a first audio amplifier provided in the portable computer and a second audio amplifier provided in the docking station. These two amplifiers amplify the audio output signal fed from the audio chip. A controller is provided for detecting the presence of the docking station, and in response thereto outputs a signal which disables the first audio amplifier. This controller activates a switch that turns off the first audio amplifier. Also, the presence of the docking station is determined by a signal having a voltage level representative of the presence of said second audio amplifier. Thus, a simple audio processing circuit is provided so as to eliminate the duplicated audio chip in the docking station.

Abstract: A docking station that has means for detecting a docked-signal that indicates that a secure electrical connection has been made between the portable computer and docking station. In addition, a locked-signal is also generated to indicate a secure mechanically locked condition once the portable computer is engaged with the docking station. The locked-signal may be generated by a photo coupler, also referred to as a photo-sensor, that is attached to the locking mechanism of the docking station. Furthermore, a power switch on either the docking station or the portable computer can produce a docking-station-power-on-signal or a portable-computer-power-on-signal, respectively. A controller uses all of the inputs to control the power supplied to both the docking station and the portable computer.

Abstract: The present invention relates to a computer having an infrared communication module for an infrared communication with external equipments. In the computer according to the present invention, since the location of the infrared communication module can change with respect to a main body, the infrared communication between the computer and the external equipments can be performed without changing the position of the computer.