If you have enrolled your mobile device in Duo, you can receive multiple SMS Passcodes sent via text message to your phone. Each passcode can then be used once at sign-in. You will need cell phone service to receive the text message, but the passcodes can be saved for later use.
You can use each code that you received in the text message one time when logging into a Duo protected University application. These codes are valid for up to 60 days.