DESCRIPTION OF PARTS
10
2 . 5. 4 Cable lengths and types
Cable lengths should be restricted to those defined below:
Figure 2.11 Cable lengths
Note:
The total maximum attenuation of the cable attached to the network port must not
exceed 6dB when measured at 1
024 MHz. The frequency/attenuation characteristic of the
cables attached to the network port shall follow a root frequency law. This port type is
approved to CTR12, CTR13.
2. 6 Alarm Extension (RJ45)
The alarm extension is an RJ45 female socket mounted on the rear panel of the unit. It allows
the connection of major and minor alarm relay contacts to a remote indicator such as a bell
or a lamp. The alarm relay port is regarded as a SELV port within the scope of EN41003.
Mains power failure is registered via Normally closed contacts as a major alarm.
Figure 2.12 RJ45 alarm extension layout
Cable
Max Length
(metres)
Belden 8132 (28 AWG)
175
Belden 9841 (24 AWG)
300
Pin
Function
1
Major Normally Closed
2
Major Normally Open
3
Major common
4
Not connected
5
Minor Normally Open
6
Minor Normally Closed
7
Minor common
8
Ground
