So I read this article ....... http://line6.com/community/servlet/JiveServlet/previewBody/1337-102-2-2182/Community_%20Control%20An%20SV112%20and%20Flextone%20IIIXL...pdf .

Here is what I did and make 1 FBV MkII Shortboard operate 2 LownDown amps (LD 400 Pro & LD 300 Pro).

Tools needed:

Network Crimpers

Side cutter

Electrical Tape

CAT 5e cable

3 - RJ47 plug ends

With two cables (CAT 5e) whatever footage needed

Put 3 RJ47 plug ends on (Color Code: 1 - Orange/White, 2 - Orange, 3 - Green/White, 4 - Blue, 5 - Blue/White, 6 - Green, 7 - Brown/White, 8 - Brown

Now you have 3 plug ends on and one cable end with nothing

ONLY use wire 6 (Green on this open end)

Strip some cable off the cable with two RJ47 plug ends (rotate your network crimpers around cable in two spots about 6" away from each other, carefully cut/split from one cut to the other cut (6" apart cut)

Take the number 6 wire (Green) and cut it

You should have 3 bare number 6 wires (Green), strip each of the 3 and twist together

Now tape the crap out of it

You have one cable with all 8 wires used - put one end in your FBV board and the other end in your main amp

The cable connected with only the number 6 wire (Green) goes to your second amp

FBV MkII / RJ47{-----------------------------------------------------------}Amp 1 / RJ47 - All 8 wires used both ends

                                  |

                                  |_____________________________________________}Amp 2 / RJ47 - All 8 wires

     Only number 6 wire (Green)

       is connected on this end                                                              

Switching banks works on both amps with one FBV MkII Shortboard

Good Luck,

    Joe