Keep it simple, don't get too bogged down with stupidly complex communication codes, they just confuse people which missed the point really.
The 11, 21, 43 idea is fine if you (and your team) are comfortable with it. Last year the team i was on used Spirit 1, Spirit 2 etc for our side losses and Team 1, Team 2 etc for kills. That way it is easy to tack on descriptions like "Team 3 back left!!". Body count must always be known but it is useful sometimes to make sure your team knows where guys have gone from so that if blind spots are created the bunker monkeys can spring into action.
Other useful and common calls are words to shout to make sure your team get their guns up and rolling, something simple to make sure that everyone is together. I think Nexus used to call 'Seven!' out occasionally and make sure everyone repeats it togther......stuff like this helps your team focus sometimes and work together so the wheels don't fall off the waggon at critical moments. Its good to have calls for if guns go down as well, something to shout out to your team to let them know you're in doo doo and might not be able to provide cover. After Field walking it's usual to establish some key words for secondary moves and set plays, something that the back/mid guys can shout out to know that other team members can execute and planned moves. Keep it simple though, don't go overboard.
When calls are made make sure that EVERYONE on your team knows about it....shout it out and just keep shouting until you can get your entire team shouting it out. Your mid-guys need a good voice to make sure that messages travel between the team. Too often have i seen fat backguys shout out calls to their font guys to move but they don't hear as they are too far away and the mid-line doesn't relay the message
Don't be too fuseed about communication, it is not the be all and end all of 'team work'. Just keep it simple and make sure everyone is well versed, otherwise it doesn't work as no one can remember the right call and doesn't bother. You see the guys on Dynasty or Legion, they don't have loads of complex codes, usually some for body count and the odd ones for planned moves. Their team work is implicit, not explicit....they play and train so much together that they all have a good understanding of each others behaviour. Interestingly enough a lot of conversation between Dynasty players I've seen is almost just talking to each other between bunkers, not big shouty calls.
