^mjeri ...Thanks for the reply bro. But wont just plain recharge or top just add balance to the card ? How will it know to activate the unlimited plan ? You getting my point naa.... I mean plain recharging will only either increase the validity or credit the balance on the sim. How to activate the unlimited plan on it ? Like for Airtel we dial *567# and send few sms commands which activates a certain gprs plan on it. How to do that here in case of BSNL 3G .. ? I dont want to end up with 1500 rupees worth of talktime 
