Whats the number to show caller ID?

Question

what is the numbers u dial before dialin the phone number that unblock caller ID not the 1 that DUZ block it i wat to no how to UN block it

Answer 1

Dial *82 before dialing the number. e.g *821(x*x) - x*x - XXXX

Answer 2

But if you use a phone card for making the calls then *82 wouldn't work.