Phone Number Format for Mobile Dialing

A downstream database-level user of employee phone number data in PeopleSoft HCM is asking us to change the default north american phone number format from 999/999-9999 to 999-999-9999, which will allegedly allow users of their iPhone app to tap the phone number for dialing. I am seeking confirmation on whether the 999-999-9999 format is an industry standard for mobile phones to allow one-tap dialing, and if so, whether PeopleSoft plans to modify the default format.

Thank you in advance for any insight you can provide.

Christine