A truetone is a ringtone which has been encoded with a sampled audio format such as MP3, AAC, or WMA. It is also referred to as a mastertone or realtone.

Ringtones started the mobile content market by demonstrating a demand for customization, initially amongst teens but then extending into the mass market. The first generation of ringtones were monophonic instrumental renditions of popular and sometimes original tunes. Users could pay to download ringtones to their mobile phones, optionally attaching them to incoming calls from select individuals in their address books. Second generation polyphonic ringtones first became popular in 2002 and encoded sequences of MIDI commands that provided higher fidelity, but these too are purely instrumental. In 2004 ringtones represented a $4 billion global market, almost all of it outside the United States of America.