Reliance Chairman Mukesh Ambani announced on Friday the launch of the device - aimed to draw tens of millions of low-income users to its telecoms venture Jio's service - a day after the oil-to-telecoms conglomerate posted "surprisingly robust" results, fuelled by improved refining margins.
Shares in Reliance rose as much as 3.9 percent to Rs 1,588, their highest since January 2008, but its telecom rivals slumped on worries about the intensifying competition in the sector, with Bharti Airtel Ltd and Idea Cellular Ltd down as much as 4.1 percent and 7.3 percent, respectively.
The Reliance earnings, combined with Wipro Ltd's $1.71 billion share buy-back plan and upbeat results, helped lift investor optimism.
The Sensex was up 23 points or 0.07 percent at 31,928 and Nifty was at 9,879, up 6 points or 0.06 percent.
Wipro jumped up as much as 8.1 percent to their highest since April 2016 and was the top gainer on the Nifty IT index, which was up 2 percent.
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