Potter PFC-5000 Series - Manual (Page 6)

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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 confi gured by default as Class B (Style B). They may be globally (all or none) confi 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 Notifi cation Appliance Circuits (NAC).