11-99 is a police code for emergency officer assistance in the California Highway Patrol's published list. Other departments use different signals: San Antonio's cited manual uses 10-15 for an officer or firefighter in trouble, while Phoenix lists 999 for urgent officer help. The department is part of the answer.
Emergency Help and Routine Cover Are Different Requests
A request for another unit does not always mean an officer is down. Routine cover, an urgent assistance request and a response to an immediate threat are different situations. The code and the words accompanying it carry that distinction.
For example, the San Antonio manual differentiates 10-11, a cover-officer request, from 10-15, an officer or firefighter in trouble. A listener who applies the common prisoner-in-custody meaning of 10-15 would miss the distinction entirely.
Help Signals in Named Agency Documents
| Assistance signal | Meaning in the named source | Listed this way by |
|---|---|---|
| 11-99 | Officer requires help, emergency | CHP |
| 10-15 | Officer or firefighter in trouble | San Antonio PD (TX) |
| 999 | Officer needs help urgently | Phoenix PD (AZ) |
| Code 20 | Officer needs assistance - emergency | San Jose PD (CA) |
These are examples of how the same search intent maps to different systems. They do not form a combined emergency protocol. The 11-99 reference compares its specific California definitions, and the Texas guide gives the San Antonio document context.
What an Assistance Signal Does Not Establish
A help signal tells other personnel that assistance is requested under the agency's rules. By itself it does not tell an outside listener what caused the request, whether a weapon is involved or whether someone has been injured. Those details require additional information.
Some published lists explicitly use officer-down language while others say help or assistance. Preserve the wording of the source rather than making every entry more dramatic. A serious request is still not a complete account of the incident.
Request, Response and Radio Priority
Code 3 often describes the response to an emergency. Code 33 commonly reserves a channel for emergency traffic in the cited California documents. Neither phrase automatically identifies the original reason for the call.
A scene update such as Code 4 can later say no further assistance is needed in agencies that use it that way. It does not erase the original request or establish the final outcome. This separation helps explain a sequence of broadcasts without turning each code into an incident diagnosis.
Finding the Local Meaning
Use the agency's published communications material and its date. When the code comes from an old recording, a manual from that period can be more relevant than a recent generic list. Keep unknown local wording unresolved rather than borrowing a definition from another state.
The 11-code guide, scanner reference and main hub provide routes into those different systems. These pages explain public references and do not direct an emergency response.
FAQ
Does officer needs help always mean 11-99?
No. CHP uses 11-99, while the sources here also document San Antonio 10-15, Phoenix 999 and San Jose Code 20.
Is a cover request the same as officer down?
No. The wording and urgency differ by agency. San Antonio's cited manual separates a cover request from its trouble signal.
Does a help code tell me an officer was injured?
Not by itself. An assistance request is not a complete description of the circumstances or outcome.
Are 11-99 and Code 3 interchangeable?
No. One can request assistance while the other describes an emergency response. Use the agency's wording for each.
Sources
- CHP 254 – Aural Brevity Card (01-2021 v2), California Highway Patrol. Official Checked October 2026
- General Manual 403: Communications, San Antonio Police Department. Updated December 21, 2016. Official Checked October 2026
- Phoenix Police Department – Radio Codes – Numerical Order, Phoenix Police Department. Updated 3/17/26. Official Checked October 2026
- SJPD 10-Codes (study guide), San Jose Police Department. Updated 10/15/18. Official Checked October 2026