Ericsson MINI-LINK TN R4 ETSI, Technical Description, Page: 115 / 149

Management
• Performance data for the Radio Terminal is described in Section 4.8 on
page 104.
Performance data is stored in a volatile memory, so that a restart will lose
all gathered data.
5.3.2 Bit Error Testing
Each NE has a built-in Bit Error Ratio Tester (BERT) in all plug-in units
carrying traffic. The BERT is used for measuring performance on E1 interfaces
according to ITU standard O.151. A Pseudo Random Bit Sequence (PRBS)
with a test pattern 2
15
–1 is sent through the selected interface.
As with loop tests, bit error testing may be used for system verification or for
fault location.
Plug-in
Unit
BERT
E1
6668
TDM Bus
NE or
External equipment
Figure 84 BERT in combination with an external loop
The BERT is started and stopped by the operator and the bit error rate as a
function of the elapsed time is the test result. The test can be started and
stopped locally or remotely using the management system.
Several BERTs can be executed concurrently with the following limitations:
• One BERT per plug-in unit
• One BERT on a protected 1+1 E1 SNCP interface per NE
Note: BERT is not valid for MMU2 E/F.
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