Your USB device is plugged into the USB MIDI Host mkII instead of into a computer. It provides MIDI In & Out sockets for USB MIDI keyboards and controllers which have only a USB B type socket. For example, used with a USB-Solo, it allows the USB-Solo to be used in a standard MIDI setup, just like a Pro-Solo. It has a USB Host port (USB A type socket), a MIDI In and a MIDI Out (both 5 pin DIN). MIDI data received at the MIDI In socket will be sent to the USB device. MIDI data received from the USB device will be sent to the MIDI Out socket. The MIDI USB HOST is powered by a regulated 5V mains adaptor (supplied), and can supply up to 1 Amp of buss power to the attached USB device. This product is supplied with a multi-region power supply suitable for use in most countries.