Reliance Industries Limited (RIL) will start taking online registration for its free SIM cards to deliver the same to customer's doorsteps. "After that the Jio SIM card would delivered to the applicant's address in 5-7 days," the site says. The website quoted official sources who said the service has already been tested and ready to be rolled out in metro cities. Reliance Jio 4G SIM card is free of cost and comes with the company's 'welcome offer', which will give users an access to free unlimited data till December 31,2016. Another reason for the huge demand of Jio SIM card is that all voice calls on the network are free and roaming charges within India has been dropped.