4 in 4 out usb midi interface Superior quality FCC,CE,RoHS Short delivery time 4-in 4-out usb midi interface Model:W-819 Product Description4 input 4 output ... mode and Through modes as below: 1. Used as USB MIDI with 64 channels, 4 input ports, 4 output ports, user choose the ... one port input(can change between input 1, input 2, input 3 and input 4), four ports output synchronously Update Date:2011 ...