011 - US exit code; dial first for international calls made from the USA or Canada
43 - Country Code for Austria
Phone Number (may not begin with 0) - Austrian phone numbers do not have a standard length; minimum length is 4 and maximum 13 digits
sample call from US to a landline in Vienna:
011 43 1 ??? ????
How to dial to Austria cellular:
dialing format for calls to a cell phone:
011 43
6?? ??? ????
some cell numbers may have less or more digits
although all Austrian mobile numbers start with 6, there are also geographic area codes using 6 as the leading digit; see this page to find out whether a phone number is a landline or a mobile phone