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by newsbinator 1640 days ago
> iOS devices discover their own number by texting a known Apple number and getting the response via the Internet, they'll then populate this field out of courtesy but it's not necessary for functionality

TIL! Is that why in some countries and some SIM cards my iPhone can automatically report its own phone number (when I look at my own profile under 'Contacts') and in some countries it doesn't do that?

1 comments

Yes!

Carriers who assign numbers to SIMs in advance could set that field directly. Others, either because they don't assign a number at the time of the SIM manufacture/personalization or just because they can't be bothered as it's not functionally necessary will leave it blank - in that case from my experience iPhones will populate the field with the number they get back from the iMessage & FaceTime provisioning step but again that's not actually necessary for functionality. The field is also user-editable in Settings -> Phone if you wish.