<Li> Pan-pan--Maritime / aviation urgency call . Repeated three times . Has priority over safety calls . </Li> <Li> Repeat--"Repeat last fire mission," or "Fire again ." Used when on an artillery net, or when speaking to tank or mortar crews, to indicate that the gun battery should fire another salvo using the same target information . </Li> <Li> Roger--"I have received all of the last transmission" in both military and civilian aviation radio communications . This usage comes from the initial R of received: R was called Roger in the radio alphabets or spelling alphabets in use by the armed forces at the time of the invention of the radio, such as the Joint Army / Navy Phonetic Alphabet and RAF phonetic alphabet . It is also often shortened in writing to "rgr". The word Romeo is used for "R", rather than "Roger" in the modern international NATO phonetic alphabet . </Li> <Dl> <Dd> Contrary to popular belief, Roger does not mean or imply both "received" and "I will comply ." That distinction goes to the contraction wilco (from, "will comply"), which is used exclusively if the speaker intends to say "received and will comply". The phrase "Roger Wilco" is procedurally incorrect, as it is redundant with respect to the intent to say "received". </Dd> </Dl>

Where did the radio term roger come from
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