KT Freetel Co., Ltd. (Korea Telecom Freetel, Korean: 주식회사케이티프리텔) was a South Korean telecommunications firm, now merged into Korea Telecom, specializing in cellular, or mobile, phones. Since 1999, it has also developed extensive overseas operations. The company is credited with developing customized ring back tones. On 1 June 2009, KTF was merged with KT.