Ring back tones replace the standard "ring-ring" sound heard when a call is connected and you're waiting for the other person to answer. Rings are replaced with content such as music, jokes, or personal messages that entertain waiting callers. They replace a run-of-the-mill sound with something fun and creative. A ring back tone service has the potential to generate more revenue per subscriber than a ringtone service. Downloaded mobile ringtones is represent ways for service providers to tap new revenue streams. With ringback tones, service providers can leverage the things that helped make ringtones a hit, such as the ability to personalize and liven up something otherwise mundane. Ring back tones work with any phone, old or new, wired or wireless.