Johannesburg - Competition within the SA telecommunications sector will drive tariffs down in 2011, according to telecommunications group Nashua Mobile.Tim Walter, general manager for product and marketing at Nashua Mobile, said on Monday that voice calls would keep getting cheaper in 2011. "In the mobile market, a more aggressive Cell C and a new entrant in the form of Telkom's 8ta could shake pricing up," he said. "Interconnect tariffs are set to drop again in March, which may give some operators and service providers scope to slash retail call rates. Telkom, meanwhile, will find itself under pressure to drop its retail rates to compete more effectively with voice-over internet protocol (VOIP) services and providers," he said.Nashua Mobile is a wholly-owned subsidiary of the JSE-listed Reunert [JSE:RLO]. The group also highlighted tablet computers as a mainstream entrant in 2011, following the success of Apple's iPad.Walter also pointed to the rise in Android technology. The Android operating system has already seized 25% market share across the world and looks likely to grab market share from the likes of Nokia and BlackBerry smartphones in SA this year. "Android is building massive momentum around the world - technology analyst Canalys says it is growing at twice the speed of its competitors, " he said. Nashua Mobile said that falling prices of ADSL data, paired with growing interest in online media services, online gaming and other demanding consumer applications, would also drive growth of the ADSL market this year.