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There are several ways to use Duo codes if your phone is not connected to a Wifi network or Data service. If you do not have access to Wifi or data service you can generate a code with the app. That could be useful if you have a wired network connection for your laptop but no wireless or cellular for your phone. You can also send a set of 10 codes to your phone via SMS. If something happens to your phone and you can not use Duo push or generate a key with the app, or even receive SMS codes, you can visit the following site to get a list of 10 codes that you can use:
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