I am electronically illiterate so this may be totally wrong.
Could it be the difference between US NATO plug/socket vs UK NATO plug/socket?
See
http://www.pprune.org/rotorheads/303...dset-plug.html
John
PS Could there be a more blatant example of bloody useless national bloody mindedness than the US vs UK NATO plugs being wired differently! (I obviously like the word bloody!).