Electric and Electronic Equipment-Namely, Nurse-Patient Signaling and Communication Systems Essentially Comprised of a Master Nurse Station Communication Unit, a Bedside Calling Station and a Corridor Signal Light, All Sold Separately or as a Unit; Voice Amplification Units; Voice Paging Units; Private Administrative Telephone Communication Units; Audio Amplifiers; [ Pre-Amplifiers; ] Computerized Communication Control and Information Retrieval Units for Use in Health Care Facilities; Two-Way Communication Units with One or More Channels, in Console and Portable Form for Use in Schools and the Like; Radio Tuners; [ Record-Changers; Signal Generators; ] Power Amplifiers; Cabinets, Racks, [ Turrets and Desk Top Enclosures Specifically Designed for Housing Telephone and Communications Equipment; ] Telephones; Central Switching Exchangers; Audio Speakers and Baffles; Power Supplies; Annunciator Panels; Selector Panels for Use in Directing Communications to Selected Rooms; Bridging Transformers; Equipment Cooling Fans Specifically Designed for Use in Communications Equipment Assemblies; Tone Generators; Remote Volume Controls; [ Audio Output Meters; Compound Sound Diffraction Projectors; Underwater Loudspeakers; Electric Power Driver Units for Use in Voice and Music Reproduction; ] Microphones; Microphone Stands; Call Origination Switches in the Nature of Controls for Two-Way Communication Systems; Intercoms; Multipurpose Communications Unit for Use in Health Care Facilities Such as Nursing Homes, Having Nurse-Patient Communications, Signaling and Paging Functions; and Power Supply and Electrical Junction Cabinets