No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


Loud Noise in Calls over the UA5000 Z Interface Extension Service

Publication Date:  2019-04-09 Views:  234 Downloads:  0

Issue Description

Model version: UA5000 V100R019C07


Device networking: Softswitch---UA5000 (CDI)---VRSP (ASL)---Phone


Symptom: In the UA5000 Z interface extension service, the noise in calls is loud.

Handling Process

1. Run the pstnport attribute set command to reduce the voice gain of the PSTN port on the peer end. The noise persists.


2. In test mode, run the pots loop-line-test command to simulate a subscriber loop line test. The loop line is normal.


3. Configure a hotline phone on the VRSP ASL board. If no noise is heard during the call, it indicates that the link from the VRSP ASL board to the master subrack is normal.


  UA5000(config)#spc add an-spc start 1/11/0/0 end 1/11/1/0  1  normal


4. If the phone is directly connected to the softswitch, the test is normal, indicating that the fault occurs on the master subrack or CDI board.


5. Replace the CDI board and the slot. The fault persists.


6. Minimize the board configuration and check the loop line. The CDI backplane is connected to four loop line connectors, which are redundant, as shown in the following figure.



7. Remove the second and third (from the top to the bottom) AMP connectors. No noise is heard during calls.

Root Cause

The loop line connection of the CDI board is incorrect. As a result, noises occur during calls of the Z interface extension service.


Remove redundant CDI loop lines.


When loop lines are led out from the backplane of the board, strictly comply with the pin assignments defined on the board. Ensure that the loop lines are not misplaced or redundant.


Pin assignments of the upper header of the H601CDI board



Pin assignments of the lower header of the H601CDI board