Plug and Play. The best-selling MIDISPORT 4x4 is a four-in, four-out, USB Midi interface for Windows and Macintosh. The 4x4 is perfect for connecting multiple midi devices both together, and to your computer. Since it is parasitically-powered by the USB port, the 4x4 is an excellent choice for both studio and portable use. Upward Mobility. Run out of midiports? It's easy to add more to your system. You can add as many USB Midisport interfaces to your computer as you have USB ports. What is USB? USB (Universal Serial Bus) is a standard interface port on desktop and laptop computers. Nearly all recent computers provide USB ports, both Windows and Macintosh computers. USB supports the connection of up to 127 devices simultaneously, any of which may be plugged into or unplugged from the USB bus at any time -- even with the power on! Whats more, it is the perfect solution for portable users, as all recent laptops also offer USB ports. Everything remains external to the computer and therefore no compute