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Outer-Office Users Cannot Hear the RBT When Making Calls to U1980 Users Who Have Enabled the RBT Service at the Carrier Side

Publication Date:  2015-07-25 Views:  562 Downloads:  0

Issue Description

Version: U1980 V100R001C01SPC700

Network: U1980–TUP–PSTN

Originally, when a user under the CC08 is called, the calling party can hear the RBT. After the CC08 is replaced by the U1980, the calling party can hear the ringback tone instead of the RBT.
Alarm information: The calling party cannot hear the RBT.

Handling Process

Step 1 Use the LMT to trace TUP messages on the U1980.

Step 2 Analyze the ACM message returned by the U1980 to the peer end. It is found that the user idle indicator is not specified.

The ACM message is as follows:
Address complete message (ACM)
00010100 H1H0: ACM
00000000 message indicator
------00 address complete signal type indicator: address complete signal
-----0-- user idle indicator: not specified
----0--- incoming call echo suppression indicator: incoming call echo suppression not contained
---0---- call transfer indicator: no call transfer
--0----- signal channel indicator: any channels
00------ reserved: 0x0
The ACM message returned by the U1980 does not indicate whether the called party is idle. As a result, the RBT cannot be played. The RBT heard by the calling party is played by the U1980.

Step 3 Set software parameter 387 to 1. The fault is rectified.
config softargu type 387 value 1
Software parameter 387 is used to set calledstatusind of the ACM message in SS7 signal.
  • 0: Not specified (default)
  • 1: Free
  • 2: Connect
  • If the called party is busy, the corresponding announcement is played.

Root Cause

Messages are different on the U1980 and CC08.