Sistema Shyam Teleservices plans to launch on Monday a spate of internet calling plans, becoming the first telecom operator to openly break ranks with peers by encouraging subscribers to make national and international long-distance calls using any OTT (over-the-top) voice services app, be it Skype, WhatsApp, Viber, Google Chat, Messenger or FaceTime. The move by the Indian unit of Russia's Sistema JSFC runs contrary to top mobile operators like Bharti Airtel, Vodafone and Idea, which have been battling OTT voice service providers who, they say, are eating into their voice business as OTT is cheaper for users. A top Sistema Shyam executive told ET that the CDMA operator's subscribers would pay 50-75% less for national and international internet calls using VoIP apps, compared with similar calls made on regular mobile networks. The move is aimed at bolstering the company's voice-centric data services business model. Lately, Sistema Shyam has been focusing more on data services, with more than 55% of its quarterly revenue stemming from the non-voice business. The latest emphasis on internet calling plans is aimed at further growing its data earnings and hedge potential revenue expansion risks by virtue of the company's modest airwave holdings in just nine circles, especially since it didn't buy CDMA airwaves in the 800MHz band in the March 2015 spectrum sale. "Sistema Shyam doesn't support any discrimination or preferential treatment when it comes to internet services, and our latest plans give customers the freedom to use data purely for internet calls if they wish," said the executive.