DI Boxes perform several important functions: they are designed for impedance matching and balancing the signal of a guitar, a keyboard or any line-level output source, and for injecting directly the signal with very long connections to the XLR microphone inputs of a mixing console.
D20P is a STEREO passive direct box with transformers and does not require any external power such as phantom power or batteries to work. The advantage of a transformer is the possibility to avoid any electrical connection between the sound source and the mixer. This provides two huge benefits: with no electrical path, ground loops are eliminated and the cancellation of common-mode noise, like hum, is possible. D20P features two 1/4″ jack to connect a stereo keyboard, or two RCA to connect a DJ console, or a 3,5mm mini-jack to connect a personal computer, for maximum flexibility without the need of special adapters.