If your talking about Text comms:
Channel 1 = grey text, The entire arena can see your message, even enemy countries.
Channel 2 = green text, Only All fellow countrymen can see your message. "If your Green your Good"
Channel 3 = purple text, Only those who have taken off from the same field as you or are in the same room (tower) can see your messages.
Channel 4 = red text, Only fellow squadmates.
Channel 5 = yellow text, Only those who are in the same mission.
Voice comms have 2 default channels The primary uses the "t" key for the mic and comunicates to those on a configurable channel, generaly for squad use, but you can also tune it to channel 5 for mission voice. The other voice channel is hardcoded for range "F12" with this you can talk to anyone within icon range of you.
