That may explain why I haven't heard this one before. I've only been using my TRX-1 for "Wildcards" and its apparently not picking this up.
I'll have to go back and see if I missed a setting or something on the TRX-1
My TRX-1 also plays the "busy signal" The SDS100 doesn't have a setting. It just plays the garbled encryption.
I noticed however, if it stays on an encrypted channel (like mine did last night) it seems to mute the audio frequently.