Using the GK-2 to control a GM-70 or a GR-100/300/700
The BC-13 was a converter box which would allow the older 24-pin pickup systems
to control the newer 13-pin guitar synth products. However, the older 24-pin
guitar synth products cannot be controlled by the newer 13-pin GK-2 or GK-2A.
These older units require a GK-1 or G-Series guitar.