Duo: Using International Phone Numbers

Rowan University supports the use of international phone numbers in E.164 format with Duo two-factor authentication. 

E.164 is the general format for international telephone numbers. Numbers are limited to a maximum of 15 digits, including the international call prefix. The number is usually prefixed with the plus sign (+), indicating that the number includes the country calling code. 

Examples of E.164 Numbers: 

E.164 general format must contain only digits as follows :

• Country code (max 3 digits)
• Subscriber number (max 12 digits)