Reliance, Aircel, Tata Docomo & Reliance GSM: Dial: *1#
Idea Dial: *789#
Vodafone: *555#
Airtel: *140*6575# ( instead of showing your mobile number directly,you will recieve a call from your number itself
)
Uninor: In Uninor you have to request money to your another known uninor number using this code: 201*XXXXXXXXXX*10# [Where 201(Toll free) is Bal Request code, X is another Uninor's 10 Digit Mobile number, 10 is a amount and # is a symbol]
After dialing this code you will get message to your known uninor number:
For Aircel,Tata Docomo and Reliance gsm dial *1# to know your mobile number