Outgoing Caller ID allows people to see your mobile phone number on the screen of their phone when you call them. If Outgoing Caller ID isn't active, your phone number won't appear and therefore blocks your identity.
For instructions on how to activate and de-activate Caller ID, please see "How do I activate/de-activate Outgoing Caller ID?"
Note: Outgoing Caller ID won't function when making or receiving an international call. Your mobile number will still appear when sending TXT messages. This can’t be de-activated.