Here's a couple of sites where you can listen to sounds of the various control channels, to help identify which one(s) you are hearing:Sorry, first post I should have included more info. Actually I worked for Entergy for thirty years and installed the original 400mHz system, but out of touch with the radio system in later years. I was able to monitor but since they migrated to Moto Omnilink, no luck. I have a BCD 396XT, BCD436HP, AOR 8200, and TRX1. I still have a friend in telecom that I need to contact, he has retirement plans. I can hear the data channels, not sure about the difference in how they sound. I do have Unitrunker. Original post was a quick shot to see if there was anybody listening close by. I haven't been pursuing this much lately, but definitely need to do more research.