A converter capable of making a five-wire or six-wire resistive touch screen compatible with a four-wire controller comprises an encode-decode circuit composed by at least two multiplexers and a signal amplification analog circuit; wherein the signal amplification analog circuit receives, analogizes and amplifies and inputs the signals transmitted by the four-wire controller to the encode-decode circuit thereby controlling the multiplexers whether to receive or process a non-encoded voltage signal and to output the voltage signal re-encoded by the multiplexers. Therefore, it recomposes, re-encodes and re-decodes the voltage signals (I/O signals) output or input by a five-wire or a six-wire touch screen so as to make the processed voltage signals compatible with the four-wire controller for processing.

The invention provides a coordinates input device capable of detecting coordinates with high accuracy by eliminating errors that could be contained in detected voltage depending on the condition of the pressure applied to a coordinates input section. When pressure is applied to a plane resistive sheet of the coordinates input section, the maximum voltage applied to the coordinates input section is detected by means of an A/D converter prior to the detection of the coordinates, and correction is made by a reference voltage regulating circuit so that a reference voltage becomes equal to the maximum voltage. Thereafter, the A/D converter converts the detected voltage to digital data on the basis of the corrected reference voltage, for calculation of the coordinates. Errors that could be contained in the detected voltage when detecting the coordinates can thus be eliminated.

A cathode ray tube display device has conductive plates mounted adjacent the four sides of the CRT faceplate. These plates are positioned to sense electromagnetic noise radiation generated by the CRT. The plates are coupled to differential circuits so that normally the noise signals generated in the plates cancel. However when a finger or other object is placed at or near the CRT faceplate, the noise radiation field is disturbed, and the changed signals generated in the plates are sensed by the circuits to provide output signals indicative of the coordinate position of the object at the faceplate. The plates are preferably mounted in the front bezel of the display cabinet.

An apparatus for use particularly in department stores or supermarkets, which apparatus comprises a computer and a storage unit, and is designed as an information and display system. This apparatus allows a user to select desired information stored in the storage unit in a simple and reliable manner. Moreover, direct dialogue between the user and the apparatus is possible. To these ends, a large area contact or sensor bank assembly with an associated signal carrier are provided. Upon approaching or touching an area of the signal carrier, a signal is transmitted to the computer. At least one output unit releases information from the storage unit visually and/or acoustically, which released information is selected through the computer in relation with the above mentioned signal transmitted thereto.

A man-machine interface type portable ultrasonic composite measuring apparatus includes an oscilloscope, a position-detecting panel mounted on the display surface of the oscilloscope, a keyboard for effecting a man-machine interface, and a computer which introduces position signals detected from the panel and contents designated by the keyboard. The waveforms to be observed include all objects to be measured, that can be observed in the form of electric signals and that form optimum ultrasonic echos. A position-detecting panel is constructed in the form of a touch panel.