APPARATUS AND PARTS FOR ELECTRICAL FIRE ALARM SYSTEMS; POLICE ELECTRIC SIGNALING AND TELEPHONE SYSTEMS; ELECTRIC PUBLIC ALARM SYSTEMS FOR ANNOUNCING FIRE, AIR RAID WARNINGS AND OTHER EMERGENCIES; ELECTRIC WATCHMAN'S REPORT, SUPERVISORY AND EMERGENCY SIGNALING SYSTEMS; ELECTRIC AUTOMATIC FIRE DETECTION, ALARM, AND EMERGENCY SIGNALING SYSTEMS; ELECTRIC AUXILIARY FIRE ALARM AND POLICE SIGNALING SYSTEMS; AND ELECTRICAL VOICE COMMUNICATION AND AMPLIFYING SYSTEMS