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Polarized telephone system for 3-state and 4-state systems
Polarized telephone system for 3-state and 4-state systems
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机译:用于三态和四态系统的极化电话系统
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摘要
A firefighter's telephone communication system is provided that includes a polarized telephone station that may be connected to either 3-state (detection of normal, open, or call-in) or 4-state (detection of normal, open, short, or call-in) telephone control panel, without the need to alter the telephone station.
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