Chapter 6 - Troubleshooting
Confidential and Proprietary Information of ZTE CORPORATION 157
5.
The fault locating flow is as shown in Figure 80.
F
I G U R E
8 0
F
A U L T
L
O C A T I N G
F
L O W
C
H A R T F O R
M S
E
C H O E S I N
C
O N V E R S A T I O N
Whether there is a
loop at interface A
and interface Abis
Start
YES
YES
NO
Remove the fault
of the EC
equipment
Replace the
T RM module
YES
NO
YES
Remove the echo
problem caused by the
MS fault
Replace the
TRM module
End
Whether the echo
problem is solved
YES
NO
Whether the fault occurs
only when PLMN and
PSTN network users are
on a call
Reset and replace
the DRT (EDRT)
board
6.
Troubleshooting
i.
Eliminate the MS fault which causes echoes.
ii.
Confirm whether echoes only occur on the PLMN and PSTN
subscribers in their conversation. If yes, the EC may go wrong.
iii.
Check whether loops occur at the A interface and Abis interface. If
yes, cancel the loop.
iv.
Try replacing the ETRM.
v.
Check whether alarms appear in DRT (EDRT) at BSC side, if yes,
reset the board. If ineffective, try replacing the DRT (EDRT) board.
7.
Precautions
None.
