When it comes to an audio problem involving FXO port, FXS port or GSM channel, you could use the Port Monitor Tool to do Port Monitor directly on S-Series PBX web.
However, there is not a similar option for BRI&E1 trunks in S-Series PBX now.
But don't worry, BRI&E1 trunks can be recorded as well via SSH.
1). Please enable FTP and SSH in S PBX Security Center first.
Note the SSH password for login.
2). Logging in your S PBX 's Command Line Interface(CLI) via PuTTY or other SSH tools.
Download and install Putty on your PC: http://www.yeastar.com/download/tools/putty.exe
Input PBX IP and SHH port 8022 in Session page.
3). The default username is support and password is what you note from PBX in above step 1).
For more detailed info about SSH login: How-to-Log-in-SSH-of-Yeastar-S-Series-VoIP-PBX
Right-click the current putty to duplicate the current SSH window.
Two SSH windows are required: one for confirming the channel is in use and the other for Port Monitor.
4). Choose one SSH window and input ( cat /etc/dahdi/ysport.conf ) and Enter.
As what is shown in the picture, one BRI trunk has 2 channels and one E1 trunk has 30 channels, so we need to figure out which channel is in use for the test first.
Input ( asterisk -vvvvvvvvvvvvvvvvvr ) and Enter.
Have one call test by using the specific BRI trunk or E1 trunk.
Input ( pri show channels ) and Enter.
Then you can see the channel 1 is in use and please switch to step 5 quickly to make sure the call is monitored completely.
5). Switch to the other SSH window fastly and start the Port Monitor.
Below takes channel 1 as an example(r1.raw and t1.raw are the file names for the Port Monitor log and you can change them as per your need):
Input ( /ysdisk/support/bin/dahdi_monitor 1 -v -r /ysdisk/support/tmp/r1.raw -t /ysdisk/support/tmp/t1.raw ) and Enter.
Once you finish the call test: Click ( Ctrl ) and ( C ) at the same time to stop the BRI trunk record.
6). Access to PBX FTP in your PC: ftp://x.x.x.x/
Use username support and password noted before to login.
Go to support>tmp, and you could find the recorded files for channels.
7). Use Audition software to open the .raw file and analyze it.
Send these files to Yeastar Support with detailed issue descriptions if you don't know how to analyze them.