AVi VOX Problem

Hi all,
I have just swapped my Pro AVI over from my 2007 GS 1200 to a 2009 ,I have connected everything up just as before but now I have a problem with the VOX.

When I speak into the mike the vox activates but switches on and off very fast giving very broken transmission ( sounds a bit like a motorboat in the ear phones) .
I have not changed anything at all , any help ?


Thanks,
Dave.

Update

Just for any of you outthere here is an update,
The interference appeares to have been coming from my Kenwood TK3201Radio that I had located under the seat, ( as on this model there is enough room) , with the radio in the tool tray the interference was present but if I moved it away by as little as 6" then it went away. The power from the Autocom and radio are coming from the aux power so maybe that has somthing to do with it,
Anyhow all fixed now .
BR
Dave