... Short delivery time 4-in 4-out usb midi interface Model:W-819 Product Description4 input 4 output USB MIDI Interface, support ... 64 channels, 4 input ports, 4 output ports, user choose the input port and output port in computer; 2. Can be used as ... 1, input 2, input 3 and input 4), four ports output synchronously Update Date:2011-11-8 00:28:48