2
Document Conventions
Circuits and Zones
The term
circuits
refers to an actual electrical interface, initiating (detection), NAC (signal), or relay.
The term
zone
is a logical concept for a
fi
re alarm protected area, and will consist of at least one circuit.
Often the terms
zone
and
circuit
are used interchangeably, but in this manual the term circuit is used.
Wiring Styles
Initiating circuits
are con
fi
gured by default as Class B (Style B). They may be globally (all or none) con
fi
gured as Class A
(Style D) as described in System
Confi guration
on page 28. This operation uses odd and even pairs of two-wire Class B (Style B)
circuits to make one four-wire Class A (Style D) circuit, thus cutting in half the number of available initiating circuits.
Indicating circuits
may be individually wired as Class A (Style Z) or Class B (Style Y) without affecting the number of circuits
available (see
Field Wiring
on page 12). Indicating Circuits may also be referred to as
N
oti
fi
cation
A
ppliance
C
ircuits (
NAC
).
