hi,as per title,does anyone know of a bluetooth intercom that is fully vox operated,ie no pressing buttons to speak to passenger.i recently purchased a cardo freecom 2+duo,which works fine(only used 3 times)but after about half an hour one or both of the units intercom switches off and we have to press a button to talk again,is there any unit which works as my old autocom which was totally vox operated.cheers alan