A subdialog question allows you to apply additional logic to your survey using an external VXML document.
Subdialog URL is the link to the subdialog.
Result is the response the survey might expect back from the webservice.
Skip logic is an advanced choice option that redirects the respondent to the designated page based on the result from the subdialog. This feature is turned off by default. To enable skip logic, clicking the question's settings icon and select “Yes” for the Show Skip Logic option.