Firmware version: Any
Create one SIP register trunk which applied from SIP provider on U-Series PBX, the status of the SIP trunk shows unreachable after a while. But the SIP trunk works fine on S-Series PBX.
Compare the SIP package of U-series with S-Series.
1. In the SIP message captured on U-Series, SIP provider didn't respond the "OPTIONS" message of U-Series.
2. In the SIP message captured on S-Series, SIP provider respond the the "200 OK" of S-Series PBX.
3. The difference between the two logs is the "From" field in "OPTIONS" message.
Customize the "From" field for U-Series in SIP message by SSH.
Step.1 Login the device via SSH.
Step.2 Type "vi /persistent/custom-cfg/sip_custom.conf".
Step.3 Add the following command to the sip_custom.conf, and the 123456 is the number of the trunk, it same as username normally.
callerid = 123456 //123456 is the caller id offered by SIP provider.
Step.4 Type <Esc> and ":wq" to save the files.
Step.5 Type the following two commands to make the script effect.
root@MyPBX:~# asterisk -rx 'module reload'