The logic is very simple, but it only works on airtel sims.I brought it here for us all to test it and see.If it works out, please comment and show it to all fellow members.Can you imagine,firstly,I was given 100mb when I put into action *420#.Secondly I was also given 4100 min. airtime free call and 25 Mb valid for thirty days when I put in to action *317#. type and see...........,