If you’re training or writing a plan, include a code-to-plain-language reference card near every radio. 9. Quick Reference Card (Print & Post in HQ) | Say | Instead of | |-----|-------------| | “Acknowledge” | 10-4 | | “Location?” | 10-20 | | “Arrived” | 10-97 | | “Emergency – clear channel” | 10-33 | | “Need backup” | 10-78 | | “Scene safe / no help needed” | Code 4 | | “Out of service” | 10-7 | | “In service” | 10-8 | Would you like a printable one-page PDF version of this guide or a template for creating a custom codebook for your organization?

1. What Are Emergency HQ Codes? Emergency HQ codes are standardized numeric or alphanumeric signals used within a command center (Headquarters) or between field units and HQ. They convey critical information — status, requests, or threats — quickly, often over radio channels where clarity and brevity are paramount.

| Code | Meaning | |------|---------| | Code 1 | Available / standby | | Code 2 | En route | | Code 3 | Emergency response (lights/sirens) | | Code 4 | No further assistance needed / scene safe | | Code 5 | Undercover / stakeout | | Code 6 | Busy / investigating | | Code 7 | Out of service (meal break) | | Code 8 | Fire / hazmat request | | Code 9 | All units respond (general alarm) | | Code 99 | Major emergency / active threat | Within an EOC or command center, codes often refer to facility status:

| Code | Meaning | |------|---------| | 10-1 | Poor reception | | 10-2 | Good reception | | 10-4 | Acknowledged / OK | | 10-7 | Out of service | | 10-8 | In service / available | | 10-9 | Repeat last message | | 10-10 | Negative / no | | 10-20 | Location | | 10-33 | Emergency traffic (clear channel) | | 10-78 | Need assistance | | 10-97 | Arrived at scene | | 10-98 | Finished last assignment | Used to track readiness of personnel, vehicles, or command posts.