General Police Radio Communication Terms (common globally):

CodeMeaning
Code 1Urgent response with lights and sirens.
Code 2Non-urgent response, no lights or sirens.
Code 3Request for backup or additional units.
Code 4The situation is under control, no further assistance is needed.
Code 5The officer needs immediate assistance (officer in distress).
Code 6Medical assistance is required.
Code 7Fire brigade required.
Code 8Hazard or dangerous goods present.
Code 9Permission to leave the scene.