9.2.2 Internal Communications Port
The 9600 baud internal communications port is provided to permit the connection of Add-Ons within
the FACP. The port also provides the 27VDC (up to 400mA) to power the modules. The port
conforms to AMPAC’s standard RJ45 8 pinned design.
9.3 Input Interfaces
9.3.1 Supervised Digital Inputs
Four supervised inputs are provided. Each input is supervised independently and designed to
operate with a 10K end-of-line resistor. Termination is via a 5mm pitch screw terminal block.
9.4 Fire Detector Analogue Loop Interface TB2
Two loop driver circuits capable of sourcing a maximum of 500mA of current for loop devices are
provided. The connection to the analogue loop is capable of communication with devices using
Apollo Discovery/XP95 protocols. Termination is via a 5mm pitch screw terminal block.
The loop is capable of being driven and sensed from either side or both sides of the loop
simultaneously. To reduce heating effects the driver is based on D-class switching topology and can
be operated in single-ended or redundant modes
The return signal of the loop is sensed using analogue to digital converters which allows analysis of
total loop current and improves rejection of incorrect signals. A noise reduction technique utilizing
common mode noise rejection has also been employed
9.4.1 Detector loop Isolator Installation
In applications where it is not necessary to use an isolating base for each detector, up to 20
detectors may be installed between isolating bases.
Note: Refer to Apollo Isolating specifications and guidelines for further details.
If a short circuit or abnormally low impedance occurs, the base isolates the negative supply in the
direction of the fault. When the short circuit is removed the power will automatically be restored.
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