Across the Line has been supporting new Irish music since 1987. Bands such as Ash, Snow Patrol and Two Door Cinema club have received their first airplay and sessions on ATL with former presenters such as Mike Edgar, Donna Legge, Colin Murray, Stuart Bailie, Paul McClean and Rory McConnell.

The Monday night radio show with current presenter Rigsy is weighted towards rock and indie music, while the Friday night/Saturday morning slot specialises in dance and electronica, fronted by Psycatron's Paul Hamill. The programme regularly records live gigs and broadcasts live from venues across Northern Ireland with the occasional foray to the major Irish rock festivals.

A sister television series, ATL TV, ran from 2004 until 2009 featuring live performance, specially made videos for local bands and interviews from major recording artists.