DESCRIPTION OF PARTS
5
2. 4 Unbalanced E3/DS3 Line port (BNC)
The network is connected to the BNC connectors at the rear of the unit as shown below :
Figure 2. 4 BNC connection
Cable lengths should be restricted to those defined below:
Figure 2. 5 Cable lengths
Note:
The total maximum attenuation of each of the cables attached to the network port must
not exceed 6dB when measured at 17.184 MHz (E3) or 22.368 MHz (DS3). The frequency/
attenuation characteristic of the cables attached to the network port shall follow a root
frequency law.
2. 5 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. 6 RJ45 alarm extension layout
Pin
Function
Tip
Signal
Ring
Shield
Cable
E3 Max Length
(metres)
DS3 Max Length
(metres)
UR202
180
155
RG59U
150
130
BT2002
160
140
BT2003
165
145
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
