Bharat Sanchar Nigam Limited (BSNL) launched a nationwide Voice over Wi-Fi (VoWiFi) service that lets users make calls and send messages over a Wi-Fi network instead of mobile towers, using their existing mobile number and dialler with no extra app. Based on IMS (IP Multimedia Subsystem) technology, it supports seamless Wi-Fi/mobile handover, is free of cost, and helps users in rural areas and inside buildings with weak signals across all telecom circles.