In 2012, ground tests of the N036 radar began on the third Su-57 prototype aircraft. The L402 Himalayas electronic countermeasures (ECM) suite made by the Kaluga Research Radio Engineering Institute uses both its own arrays and that of the N036 radar system. One of its arrays is mounted in the dorsal sting between the two engines. The system was mounted on the aircraft in 2014. Radio telephone communication and encrypted data exchange among various aircraft and also command centers (ground and sea-based and airborne) will be provided by the S-111 system, developed by Polyot. The system will be based on a modular concept and could be installed not only on the Su-57, but also on various aircraft, helicopter, and drones. "Its effective range of operation is up to " a spokesman said. "The system's reliability is guaranteed by the multiple redundancy of the main functions and cutting edge technical solutions, as well as a wide range of radio channels."