Step 1 Use the LMT to trace TUP messages. For calls routed to Bell PBX, when the peer end receives the IAI message, the peer end returns the CFL message to directly release the call even when the U1980 is reporting digits one by one, as shown in the following figure.
Since services run properly before the original CC08 is replaced by the U1980, it is suspected that the IAI message sent by the U1980 is different from the IAI message sent by the CC08.
Step 2 Compare the IAI message sent by the U1980 with the IAI message sent by the CC08. Two differences are found. One is that the orders of the calling and called numbers are different in the IAI messages. The other is that the echo suppression indicator field in the IAI message sent by the CC08 indicates that the outgoing echo suppression is not contained while the same indicator in the IAI message sent by the U1980 indicates that the outgoing echo suppression is contained.
Step 3 Confirm with the CC08 R&D personnel. The different orders of the calling and called numbers are caused by the parsing tool. The orders are the same in fact.
The preliminary judgment is as follows: Due to special settings, Bell PBX does not support the echo suppression indicator value indicating that the outgoing echo suppression is contained.
Step 4 Run the config protocol tup officeno 7 servicecontrol 100 command to forcibly disable the echo suppression function. The fault is rectified.
To restore the default setting, run the config protocol tup officeno 7 servicecontrol 0 command.
Some indicators in the IAI message obtained after the modification are as follows:
Initial address message with additional information
00100001 H1H0: IAI
--011000 calling user type: common user, which is used among city offices
00------ reserved: 0x0
------00 address type indicator: user number
----00-- circuit type indicator: no satellite circuit in connection
--00---- continuity check indicator: continuity check not required
-0------ echo suppression indicator: outgoing echo suppression not contained
0------- international incoming call indicator: not international incoming call
-------0 redirecting call indicator: not redirecting call
------0- indicator about whether all digital paths are required: common call
-----1-- signal path indicator: all SS7 system paths
----0--- reserved: 0x0
0110---- address signal number: 0x6
----0001 address signaling: digit 1