Airtel has introduced Start / Stop Service which provides Airtel customers an easy & instant way to activate or de-activate any Value Added premium service of their choice under one window of Interactive SMS session by sending SMS to the toll free number 121. Airtel Start/Stop service enables you to view and manage all your Value Added Service service through an interactive SMS session. You can reply to the SMS with the number against the service which you wish to START or STOP. The Airtel Start / Stop service works from your pre-paid as well as your post-paid connection.