In order to help prevent ambiguity or mis-hearing in the fog of war, especially when communications are rather poor quality, the Canadian military requires one to use specific rules of 'voice procedure' over the air. If one is going to use a numeral, he/she should say the word 'figures' immediately prior to the number or list of them. When things go really bad, we shout into the mike "WORDS TWICE, WORDS TWICE..." hoping that much gets through to the intended, and then we literally have to say each word in the syntax twice in succession. Apparently it solves the problem, but I never had to test it in practice...thank goodness.
I always have used four, four, oh. Two eight oh. The radio voice procedure is to use 'zero', but, when we discuss in person our military driver's license, we call the permissions "four oh fours" for the Form DND 404. Go figger.
We use, in voice procedure, "I spell..." when we attempt to spell out a word for clarity. And, of course, we use the phonetic alpabet, nicknames, arm indicators (Ironsides for the armoured corps tanks and recce vehicle component, Foxtrot for infantry...), and code words for landmarks so that listening enemy won't easily deduce our location.
"Zero, this is Two Two, I spell all after Canada: alpha, lima, bravo, echo, romeo, tango, alpha....over." It seems ponderous, but it is actually quickly acquired and goes a long way to reducing alpha, mike, bravo, india, golf...oh heck, ambiguity and mishearing.