In keeping with its simple design, the CDX-GT420IP is straightforward to operate using a combination of hard buttons and a rotary dial. With a digital-audio disc playing, the press of a button on the monochrome display will cycle through the ID3-tag information for the current song's album, the track, and the artist's name. We like the white-on-blue color scheme of the display in darker settings, but the characters have a tendency to wash out in direct sunlight. Only seven characters are shown at a time for each entry, but the tags can be set to scroll across the display. While we like the dedicated buttons for skipping between tracks and between albums (or folders) on a disc, there is no way to browse through the songs on a disc, meaning that drivers have to search through songs or albums one at a time to get to their favorite disc-based music.
With an iPod connected via the as-standard full-speed cable, all controls of the player are transferred to the stereo faceplate, and drivers can view information for track name, album name, and artist on the monochrome display. The CDX-GT420IP provides drivers with a useful means of browsing iPod songs: pressing the Mode button cycles through the familiar iPod categories of album, artist, and playlist. With one of these categories selected, drivers can use the 1 and 2 preset buttons to scroll through an alphabetized list of entries.
Holding the preset buttons down will scroll through the list at the rate of one per second. For those not interested in the effort of searching for specific songs, a Shuffle button on the faceplate turns the CDX-GT420IP into a handy one-touch iPod jukebox with options for albums, artists, playlists, or all tracks. The shuffle function is also available in disc mode, with options to shuffle between songs (on standard Red Book discs) or albums (on a multi-album MP3 or WMA discs).