Question: how to activate sms pack in airtel by ussd?
Answer: Airtel to Airtel SMS. Validity. 1 Day. Activation. Dial. *166*2# Activate. Airtel to Airtel SMS. Validity. 1 Day. Activation. Dial. *166*3# Activate. Airtel to Airtel SMS. 400. Validity. 30 Day. Activation. Dial. *166*4# Activate.