PSTN to sip termination number in India (Need to call from India cell phone to US (sip phone ,computer) for free)

Hi, I am in US and my family is in India, I am aware of sip etc. I was wondering if there is any provider which provides PSTN to sip termination for free , Since my family can only call landline , cell phone within India . I want that they should be able to call any PSTN no (Local charges -withing India) and that operator provides me some sip termination or a call on its softphone etc so that they can talk on Indian rates. Please respond asap Thanks a lot Thanks Saurabh