Question: what is the difference between 10-4 and roger?
Answer: In radiotelegraphy, an operator would send “R” to indicate that he or she had received a message. “Roger” is a phonetic way to say “R.” 10–4 is one of a group of “10 codes” that are used by law enforcement Citizens Band radio operators as a shorthand for common phrases. 10–4 is short for “message received.”