The above picture shows the internal MIDI connections of my gig-rig.
For those who don't know what MIDI (Musical Instrument Digtal Interface) is about, a good explanation can be found at www.midi.org.
There is one MIDI input device in the gig-rig; the Yamaha WX-5 wind controller. The WX-5 is not connected directly to the sound modules, but to the transmitter of the Kenton MIDISTREAM wireless MIDI system. The MIDI OUT on the receiver of the system connects to the DIY switchable MIDI THRU box.
The MIDI THRU signals are then connected to the two Yamaha VL70-m modules.