Huawei HG612 - Basic
The default configuration is for All to be selected. With that setting each mode will be tested, in turn, starting from VDSL2 and will cease once a stable sync with the remote DSLAM (or MSAN) has been obtained.
We see ADSL2 selected, in the above image, forcing that mode only to be used.
Here a typical PPPoA VCMUX encapsulated connection is configured, with a Virtual Path Identifier (VPI) of 0 and a Virtual Circuit Identifier (VCI) of 38.