User's Manual Part 2

RBS 2308 and RBS 2309 User’s Guide
Table 37 PCM Parameter Settings for Transmission Interface E1, 120 Ω
PCM Parameter Settings
Transmission Interface
E1
Network Topology
See Site Installation Documentation
Sync Source See Site Installation Docume
ntation
CRC-4 See Site In stallatio n Docum e ntation
Spare bits See Site Installation Documentation
A
B
C
Receiver Sensitivity
D
See instructions below
The instructions below describe how to calculate the cable attenuation between
the Far End and the RBS. The cable attenuation determines whether receiver
sensitivity is to be set to short or long haul. Use of long haul requires that the
equipment at the far end supports long haul.
Note: Ports C and D can also be used as a multidrop pair.
P008428C
Far End
RBS 2 RBS 3RBS 1
A(C) B(D)
A(C) B(D)
A(C) B(D)
Figure 53 System View for Transmission Interface E1, 120 Ω
1. Calculate the cable attenuation between the Far End and the RBS
according to the following formula:
Cable attenuation = cable length × cable attenuation per metre (or foot).
If multidrop is used, then calculate the attenuation of the entire RBS chain,
because R eceiver Sensitivity A (C) is determined by the total attenuation of
the chain. Receiver Sensitivity B (D) is determined by the total attenuation
to the last RBS in the chain.
2. If the cable attenuation i s less than 6 dB, then set the receiver sensitivity
to short haul.
If the cable attenuation is greater than 6 dB, then set the receiver sensitivity
to long haul.
3. Set unused ports to short haul.
The following example illustrates what is said above.
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/LZT 720 0027 Uen R8A 2006-06-27