HD Radio is revolutionizing the radio market, with more and more stations across the nation now broadcasting in clear digital sound, with expanded programming featuring more artists, more genres, more personalities and much more music than ever before. The best part of HD Radio? Itís free, and the ACD-HD expansion tuner card lets you easily add HD Radio to the companion TU-604CI multi-zone AM/FM tuner. The TU-604CI features 4 expansion card slots, allowing up to 6 separate tuners for music anywhere in the home. Additional cards are available for expanded AM/FM and XM/Sirius satellite digital radio capability, allowing you to mix and match to suit your individual tastes. Installation is a snap, just slide the card into one of the 4 available expansion slots. The TU-604CI provides independent control for each tuner module, with up to 56 stations memory each. Installers will appreciate the Ethernet connectivity, which allows web-based programming.