I design a form that prompts the user to enter his cell phone number. The platform is global and the form must therefore be able to accept any mobile number from any country.
Looking at this Wikipedia entry that lists all the international dialing codes, I see that there are less known entries
Cocos (Keeling) Islands +61 89162 Turks and Caicos Islands +1 649 Globalstar (mobile-satellite service) +881 8, +881 9
It is unlikely that users who will use this platform will live in these locations (the latter is not even a country but a telecommunications facility). However, this is not certain and some users may be required to provide mobile numbers with these codes.
To what extent should the form be accommodating with respect to these lesser known international telephone codes? I did not see them on the forms I saw on the Internet. Is there a standard list generally used?