Waterflow Switch. An assembly approved for service and so constructed and installed that
any flow of water from a sprinkler system equal to or greater than that from a single automatic
sprinkler head will result in activation of this switch and subsequent indication of an alarm
condition.
Zone. A designated area of a building. Commonly, zone, is interchanged with initiating device
circuit.
Serial interface circuit. Circuit connect to annunciator, RPM (FCA2018-U1).
Signaling line circuit. Circuit connect to field devices.
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