Elegantly simple. The UNO is a complete USB to MIDI solution, equipped with a USB connection to your computer, and a 1 In/ 1 Out 16 channel MIDI connection to your MIDI devices. The Uno works for Windows and Macintosh operating systems. Its single MIDI in and out connectors make it perfect for connecting a keyboard or controller to your computer quickly and easily. Since it is parasitically powered by the USB port, the Uno is convenient and great for portable use. Features: 1-in 1-out MIDI interface (16x16 MIDI channels). High-speed connection to USB-equipped PC or Apple computers. MIDI-Activity indicators for each port. Self-powered “ requires no external power supply. Built-in USB cable and MIDI extension cables. Includes OMS drivers for Mac OS 8.6 or greater. Windows 98, ME, 2000, and XP compatible ”true Plug-and-Play installation requires no IRQ, I/O Address or DMA channel setup. Extremely compact size. Requirements: PC: Windows 98 SE, 2000, ME, or XP   Macintosh: Mac OS 8.6 or greater, OMS 2.3.8 or greater.   LIMITED WARRANTY 1-year parts and labor.