The NHX-30G 30 station add on selector expands the NHX system to its maximum capacity of 80 stations. With a simple connection to the NHX-50M, the 80-call master station remains streamline and compact in size. The NHR-30K Expansion Trunk Card provides the additional call signaling and control functions for the add-on selector, and is installed inside the Central Control Unit. A call from stations 51-80 will annunciate on the add-on selector. Call answering is the same as any call on the master station. Routine calls can be cancelled at the master station, including the add-on selector, and any urgent calls or bedside cord-out calls must be reset at the calling location.