Apparatus for converting thermal energy to electrical energy, namely, thermoelectric converters; Apparatus for recording, transmission or reproduction of sound and images; Apparatus for recording, transmission, processing and reproduction of sound, images or data; Apparatus for recording, transmitting and reproducing sound and images; Apparatus for the recording, transmission and reproduction of sound and images; Apparatus for transmitting and reproducing sound or images; Automatic switchboar...

ultrasonic and infrared detection switches