The “ten” codes

The “ten” codes are numeric abbreviations for simple sentences developed for use in the military, police, and emergency communications over specific radio frequencies. Citizen’s Band (CB) radio users, or hams, adopted the use of ten codes to help understand other CB hams. Problems such as too much static, voices cutting in and cutting out, and difficulty in identifying the speaker and when he or she was done talking resulted in the widespread use of the ten codes. Bringing order to a chat may lead to using some common signals. Why not the “ten” codes?
Useful codes include:
10-3 — Stop transmitting
10-4 — Message Received; Affirmative
10-6 — Busy
10-9 — Repeat your message
10-12 — Stop
10-16 — Reply to message
10-18 — Urgent