T-Mobile today (Dec. 8) became the first U.S. wireless carrier to introduce ringback tones to its entire subscriber base.

T-Mobile today (Dec. 8) became the first U.S. wireless carrier to introduce ringback tones to its entire subscriber base. Branded as "Caller Tunes," T-Mobile's rollout is the largest U.S. introduction yet of ringbacks, which allow subscribers to replace the standard ringing sound one hears while waiting for a call to connect with music or other audio content.

The carrier has inked licensing agreements with Sony BMG, Warner Music Group and Universal Music Group, as well as independent labels Death Row Records and TVT Records.

A subscription to Caller Tunes costs $1.49 per month; customers then pay $1.99 per ringback tone. Initially, users may select from up to 500 tracks in such categories as country, rock, classical, dance/club, seasonal, hip-hop/rap, alternative and pop. T-Mobile expects to expand the selection on a weekly basis to reach up to 1,000 titles, which it says will be updated regularly.

The move comes three weeks after Verizon Wireless introduced its ringtone service, limited to the California market. Verizon plans to expand its service nationwide by mid-2005. Wireless operators Sprint and Cingular are expected to launch ringtone services soon as well.

T-Mobile is offering a 30-day free trial of Caller Tunes to its subscribers and will offer monthly free "Bonus Tunes," the first being Alicia Keys' "Karma."