The registration data of the SIP provider to which this SIP trunk is establishing a connection appears on this tab.

The "SIP Provider" field is simply an information field (the SIP provider is defined in the configuration of the associated trunk group).

The access parameters defined specifically for this trunk appear under "User ID", "User Name" and "User Password". Your SIP provider will provide the corresponding parameters.

Note: Most SIP providers enter only a user name and no user ID. In this case, enter the user name in both fields.