Code 6
An ambulance or medical assistance is needed.
Code 7
Fire services are required.
Code 8
Hazardous materials are present.
Code 9
Permission to leave or disengage from a scene.
Affirmative
Yes or confirmation.
Negative
No or denial.
ETA
Estimated Time of Arrival.
Backup required
Request for additional units or assistance.
Over
End of transmission, awaiting a reply.
Roger
Message received and understood.