Hello, dear!
Do you want to creat SIP trunk?
Do you want to connection U19 to the peer device.
Please see below:
How to configure SIP trunk
Log in to the web management system.
Choose Trunk > Trunk Configuration > SIP from the navigation tree.
Click Add A Peer Office in the SIP trunk configuration area.
The blue icon point:0 (the peer device) is displayed.
Click point:0 or the solid line between the local office and point:0, and set the parameters according to actual situations and the parameter description on the page.

Click OK.
When the SIP trunk configuration is complete, the line between the local office and the peer office turns green.
A green line indicates a successful data configuration, while a red line indicates that the data is not configured or the configuration fails.
Click Data Save in the upper right corner of the web management system.
For details, see
https://support.huawei.com/hedex/hdx.do?docid=EDOC1000073292&id=u1960_cfgg_00020&lang=en
Best wishes!