Being a FleetTalk System Admin (FLA), I know some customers are encrypted, depending on the user.
I use DSD+ (Fastrack) to monitor all my fleettalk sites in Florida. Some are in the clear, others are encypted.
Screen shot what your output shows and I can tell you what is going on.
ALSO, if there is no voice on the Control channel, your not going to hear voice, you have to listen to the VC.
Only single channel sites will pass voice (hybrid) on the CC. 2 Chl sites, if setup for dual mode, will also do
voice if the other channel is in use, the CC will revert to VC and pass audio, then roll back to CC. Long winded
conversations will also busy out that site if the CC is in VC mode for extended time.