ACRE Communication Quick Reference
Basic Considerations - The ABC's of Radios
Accuracy
Before you key your radio, make sure to collect your thoughts and accurately transmit your message so you can give your teammates the best information possible.
Brevity
Send your message as succinctly as possible to avoid clogging up the net. Nobody needs to hear you ramble while they're in a firefight.
Clarity
Speak as clearly as possible! Radios are interfered with by range and terrain so your intended recipient might get you with lots of static. Try to keep your voice clear (Especially if you're one of our heavily accented friends)
Radio Traffic
Initiating a radio handshake
Someone this is someone All radio traffic should begin with something like this. If you get a response, great, send your message. Otherwise, the other guy probably isn't receiving your message. More formally, it goes something like this. Bravo, Alpha In this scenario, someone from Alpha squad is calling Bravo squad. Bravo would respond with simply their callsign - Bravo And that's all there is. The Alpha person would send the message and both go on their ways.
Over, Out, Break, etc.
Over
'Over' is used to indicate that any one message is finished and others can use the net.
Out
'Out' is used to indicate that the entire conversation is over. People on the other end aren't expected to respond to this, so don't end ever transmission with 'out'!
Break
'Break' is used before the transmitter stops speaking momentarily. Maybe they need to take a breath and gather their thoughts, maybe they expect the other end to take out pen and paper, but the transmitter typically gives 3-4 seconds before finishing the message.
Break, Break, Break
'Break, break, break' is used to tell everyone to shut up, someone has something important to say. (This is also used on TeamSpeak to tell people to shut up quite often!)
Misc
Radio Check
Typically, at the beginning of a mission, people will check their radios by sending their callsign, typically a team name for your average grunt, plus 'Radio Check'. This is useful for making sure you're on the right net, making sure ACRE is working, whatever. Typical responses will be '5 by 5' or 'Loud and clear'. Probably don't transmit again and again until you get a response - People might be preoccupied!
SL Radios
If your squad leader dies, taking his radio is very much expected. Taking the radio of someone who is simply downed is done, but this is reserved for much more urgent situations, such as calling in contact. The medics typically have radio for a reason! Same thing goes for the RTO - Don't let those radios disappear.
Credit for this guide goes to by Toadball of United Operations for his imgur ACRE Quick Reference