gmail like account verification with phone call [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 11 years ago.

google recently(not very recently) started to verify new gmail accounts bt phone. when account is created and you are on the final step, a 开发者_StackOverflow中文版robot calls by phone and tell you the verification number. PHP-Side is OK but the calling section i have no idea. how can i do that? where to start?

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A good place to start would be providing the user an input field for their phone number.