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Operation
11.6.2 NAC (Signal) Circuit Types
Table 20 NAC (Signalling) Circuit Type
NAC (Signalling)
Circuit Type
Description
Silenceable Signal For audible devices such as bells and piezo mini-horns that may be
silenced either manually or automatically. While sounding, these follow
the pattern appropriate for the condition: the configured evacuation code
(default is temporal code) during single-stage alarm, or two stage
general alarm, or the alert code during a two stage system's alert (first)
stage.
Non-Silenceable Signal For audible devices such as bells and piezo mini-horns that may not be
silenced either manually or automatically. While sounding, these follow
the pattern appropriate for the condition: the configured evacuation code
(default is temporal code) during single-stage alarm, or two-stage
general alarm, or the alert code during a two stage system's alert (first)
stage.
Coded Signal For audible devices such as bells and piezo mini-horns that may be
activated in code. The code consists of 4 digits with each digit consisting
of 1-15 pulses on the signals. Each coded circuit can sound the
complete code 1 to 15 times after which signals go silent or revert to
programmed General Alarm rate.
Note: The NFPA-72 and ULC-S527 specify temporal tone. However, for
retrofits of systems that were previously approved, coded signalling is
allowed.
Strobe For visual devices such as strobes that use no code patterns (they are
continuous).