The code will be sent via a flash phone call, that will be closed immediately. The phone code will then be the phone number itself, just make sure that the phone number matches the specified pattern.
auth.sentCodeTypeFlashCall#ab03c6d9 pattern:string = auth.SentCodeType;
|pattern||string||pattern to match|
Some methods require the client to verify if the data obtained from an external source matches a certain pattern.