10-11 has several documented police meanings. An NYPD Patrol Guide procedure uses it for an alarm condition at Department of Education facilities; Phoenix Police Department lists on duty; San Antonio's cited manual uses it to request a cover officer. The number alone cannot select the right meaning.
10-11 Meaning by Agency
The comparison below gives each definition with the document that supports it. Older APCO lists are included as historical standards, not as a requirement that present-day departments follow one meaning.
| Agency or list | What 10-11 means | Source |
|---|---|---|
| APCO standard list (1974) | On duty | APCO 1974 brevity code |
| APCO recommended list (1955) | Stay in service | APCO 1955 ten signals |
| Phoenix Police Department (AZ) | On duty | Phoenix PD radio codes |
| California Highway Patrol (CA) | Identify mobile frequency - KA4993 ("S" channel) | CHP aural brevity card |
| Folsom Police Department (CA) | Confidential information | Folsom PD communications manual |
| Coral Springs Police Department (FL) | Transmitting too fast | Coral Springs PD ten codes |
| Wayne County Sheriff (IN) | Animal | Wayne County Sheriff 10-codes |
| City of Winston-Salem (NC) | Employee numberPublished by the city; the list does not name the agency | Winston-Salem police radio codes |
| New York City Police Department (NY) | Alarm conditionAlarm response at Department of Education facilities | NYPD Patrol Guide |
| San Antonio Police Department (TX) | Cover officer requested | San Antonio PD General Manual 403 |
| Ogden City Police Department (UT) | On dutyUses the State of Utah 10-code list | Ogden PD policy 25 |
NYPD: Alarm Condition in a Specific Procedure
The public NYPD Patrol Guide material names radio signal 10-11 as an alarm condition in an alarm-response procedure concerning Department of Education facilities. That is direct support for the alarm meaning in that context.
It is deliberately narrower than saying every NYPD alarm, every New York agency or every code beginning 10-11 has one identical use. A specific procedure can verify a meaning without establishing a complete citywide code dictionary. The event, agency and document context still matter.
Phoenix and the APCO Lists: Service Status
Phoenix's published radio list gives 10-11 as on duty. The APCO 1974 aural brevity list also uses on duty, while the 1955 recommended list printed in the 1957 Bulletin uses stay in service. Those are status-related definitions, unlike the NYPD alarm example.
A person finding 1011 in a general list may therefore get a plausible definition that is wrong for the recording they heard. A status update is different from an incident category or a request for another unit. The 10-code guide shows other cases where local use diverges.
San Antonio: A Request for Cover
San Antonio General Manual 403 lists 10-11 as a request for a cover officer. That document separately uses 10-15 for an officer or firefighter in trouble. The distinction is useful: asking for cover does not automatically establish that an officer is down or that an emergency has occurred.
Use the San Antonio section of the Texas guide for the complete short list in that manual. The officer-needs-help guide compares urgent assistance signals without treating every cover request as the same event.
Other Published Meanings
The CHP card uses 10-11 for identifying a mobile frequency; Folsom lists confidential information; Coral Springs lists transmitting too fast; Wayne County lists an animal; and Winston-Salem's city-published list gives an employee-number meaning. These are examples with sources, rather than guesses based on the number.
If the agency is not represented here, leave the exact meaning open until its material supports an interpretation. An alphabetical or national online list cannot determine the local codebook on its own.
10-11, Code 11 and 11 Codes Are Different Labels
Code 11 is a separate radio label with its own meanings in the collected documents. The 11-code family contains forms such as 11-44 and 11-99. Neither should be silently substituted for 10-11.
When a recording is unclear, keep the complete phrase and surrounding words. Use the Police Codes Guide to identify the code family before interpreting its meaning.
FAQ
What does 1011 mean in police code?
It can be a compact written form of 10-11. The agency determines which definition applies.
Does 10-11 mean an alarm in New York?
The cited NYPD Patrol Guide uses 10-11 for an alarm condition in a Department of Education facility procedure. This verifies that context, not every agency in New York.
Does 10-11 mean on duty?
Yes in the Phoenix list and the APCO 1974 list. Other named sources give different definitions.
Does 10-11 mean an officer needs emergency help?
San Antonio's manual uses it for requesting cover and separately lists 10-15 for an officer or firefighter in trouble. Do not collapse those entries.
Is 10-11 the same as Code 11?
No. Keep the prefix. The Code 11 comparison documents separate uses.
Sources
- Public Safety Communication Aural Brevity Code (APCO Project 14, Exhibit No. 7, p. 60), APCO (Associated Public-Safety Communications Officers). Updated 1974. Standard list Checked October 2026
- Standard "Ten Signals", The APCO Bulletin, April 1957, p. 7 (list prepared by the National Operating Procedure Committee in 1955), APCO (Associated Public-Safety Communications Officers). Updated April 1957. Standard list Checked October 2026
- Phoenix Police Department – Radio Codes – Numerical Order, Phoenix Police Department. Updated 3/17/26. Official Checked October 2026
- CHP 254 – Aural Brevity Card (01-2021 v2), California Highway Patrol. Official Checked October 2026
- Communications Manual (radio codes, p. 32), Folsom Police Department. Updated rev. 2019. Official Checked October 2026
- Ten Codes (Communications), Coral Springs Police Department. Official Checked October 2026
- Signal and 10 Codes, Wayne County Sheriff (Indiana). Official Checked October 2026
- Police Radio Codes, City of Winston-Salem. Official Checked October 2026
- NYPD Patrol Guide (public edition), part 2, New York City Police Department. Official Checked October 2026
- General Manual 403: Communications, San Antonio Police Department. Updated December 21, 2016. Official Checked October 2026
- Policy 25: Use of Police Radio, Ogden City Police Department. Updated May 16, 2022. Official Checked October 2026