Abstract: A picture display device displays a video signal supplied from a data process device. Bi-directional communication is carried out with each of a plurality of data process devices. A plurality of video signals is combined into one screen corresponding to information of the picture size of each of the plurality of video signals obtained by the bi-directional communication with each of the plurality of data process devices. A video signal, outputted when the plurality of video signals is combined, is displayed. A second control signal is generated which controls the plurality of data process devices and which corresponds to a first control signal that corresponds to a user operation. The first control signal and the second control signal are transmitted to the plurality of data process devices. The plurality of data process devices also communicate bi-directionally with each other.

Abstract: A picture display device displays a video signal supplied from a data process device. Bi-directional communication is carried out with each of a plurality of data process devices. A plurality of video signals is combined into one screen corresponding to information of the picture size of each of the plurality of video signals obtained by the bi-directional communication with each of the plurality of data process devices. A video signal, outputted when the plurality of video signals is combined, is displayed. A second control signal is generated which controls the plurality of data process devices and which corresponds to a first control signal that corresponds to a user operation. The first control signal and the second control signal are transmitted to the plurality of data process devices. The plurality of data process devices also communicate bi-directionally with each other.

Abstract: Video signals from a plurality of personal computers are written to a memory that stores video signals for a plurality of display screens through respective buffers. The video signals may be read from the respective buffers and displayed simultaneously on a single monitor. By selecting the video displayed in a portion of the monitor, the personal computer sending those video signals to the monitor may be selected for active operation. In this manner, a single set of input devices may be used to control a plurality of personal computers.

Abstract: A method of measuring horizontal frequency, which comprises the steps of resetting an 8-bit counter, which counts horizontal synchronous pulses separated from a video signal, at a time point corresponding to an edge of a vertical synchronous signal separated from the video signal, causing a data latch portion, which is operative to latch count data obtained from a 16-bit counter operative to count clock pulses having a predetermined frequency, to latch the count data obtained from the 16-bit counter at a time point corresponding to an edge of a bit output signal obtained from the seventh bit position of the 8-bit counter, detecting a period which corresponds to 128 times a horizontal period of the video signal based on a difference between counted values represented respectively by a couple of count data latched successively by the data latch portion, and measuring horizontal frequency of the video signal by calculating the horizontal frequency on the strength of the period corresponding to 128 times the hori

Abstract: Video signals of a plurality of personal computers are displayed on the same screen. In addition, using one set of input devices, a plurality of personal computers are operated. Two personal computers are connected to a monitor. In addition, input devices such as a keyboard and a mouse are connected to the monitor. Video signals supplied from the two personal computers are written to a memory that stores video signals for a plurality of screens through respective buffers. From the read start address, the address range for one screen is designated and a corresponding video signal is read. A plurality of video signals are displayed in different display areas of a display portion at a time. In addition, corresponding to a display area at which a cursor is positioned using a switch operation and an input device operation, a corresponding personal computer is selected. An output of an input device is supplied to the selected personal computer.