The master station designed to connect to network intercom exchange, and provides hands-free or handset conversation of high sound quality. Features dustproof and waterproof construction, and can be used in locations exposed to ambient temperatures ranging from -10 to +50°C. In addition to the functions of standard master station, the industrial-use station permits connection of external speaker and can take out control signal for dial-in indicator from its contact output. Station can be mounted to wall using and optional YC-280 wall mounting bracket.