The NHX-50M master station is able to receive two levels of calls and communication with up to 50 room stations. The optional 30-call add-on selector allows expansion up to 80 stations. The membrane-style control panel is simple to use, has tactile switches, and is mar-resistant and moisture-resistant, resisting damage from spills. The master station includes a handset for voice actuated communication, with a magnetic hookswitch (no moving parts). Controls include TALK button for “push-to-talk” communication, TONE OFF button to silence call tone, and OFF button to conclude communication. Easily adjustable voice and tone volume controls are located on the side, with all other volume controls located on the bottom of the unit.