Beatmatching, Beatmatching

The creation of the mp3-player allowed DJs to have an alternative tool for DJIng. Limitations with mp3-player DJing equipment has meant that only second generation equipment such as the IDJ2 or the Cortex Dmix-300 have the pitch control that alters tempo and allows for beatmatching on a digital music player. However, recent additions to the Pioneer CDJ family, such as the CDJ-400, allow mp3-player and other digital storage devices (such as external hard drives and USB memory sticks) to be connected to the CDJ device via USB. This allows the DJ to make use of the beatmatching capabilities of the CDJ unit whilst playing digital music files from the mp3-player or other storage device.

Source: Wikipedia > Beatmatching