Many mobile phone users don't have home phones anymore. That makes their mobile phone numbers the only way to reach these users. When your mobile phone number is your lifeline, though, you may be wary about giving it out. With caller ID so prevalent on mobile phones, though, calling an unknown or untrusted phone number may put your phone number in the wrong hands. Protect your mobile phone number with a simple caller-ID-blocking method.
Turn on your mobile phone. Press the green call button.
Dial *67, followed by the phone number you wish to reach.
Press the red "end call" button to disconnect the call.