I asked the same question in a chat and in fact they were surprised by the question in itself.
So far had not had an answer.
When it comes to 'interop' mode I am sure they have no protection that works with 3rd party devices. Because it needs some extra proprietary config on the radio's on both end.
And by there reaction I don't think they have it on their own product line. All focus goes to TDMA/GPS sync. I'd presume.