In APCO, Association of Public-Safety Communications Officials 10-codes, 10-0 typically indicates an "Officer In Trouble" or "Emergency Situation". It is used to signal that an officer requires immediate assistance, often due to a threat to safety or a rapidly escalating incident.
Here’s how it might be used in a real-world scenario:
- Officer: "Dispatch, 10-0! Suspect is resisting."
- Dispatch: "Copy 10-0. All units respond."
In this exchange, the officer is declaring an emergency (10-0), prompting dispatch to immediately prioritize the call and direct nearby units to respond without delay.
Because 10-0 communicates urgency and potential danger, it is treated as one of the highest-priority signals in radio traffic and typically overrides routine communications.
Historical Background
The designation of 10-0 as an emergency or officer-in-distress code emerged from the early APCO 10-code framework, where brevity and clarity were critical. In an era of limited radio coverage and shared frequencies, officers needed a fast, unmistakable way to declare a life-threatening situation.
Emergency-specific codes like 10-0 helped dispatchers instantly recognize severity without requiring detailed explanations, allowing for faster coordination and response during high-risk encounters.
Operational Usage
In active operations, 10-0 may be transmitted verbally by an officer, triggered via an emergency button, or inferred when an open microphone captures signs of distress. Dispatchers generally treat any 10-0 transmission as verified until proven otherwise.
Common situations that may warrant a 10-0 include:
- Physical confrontation or assault on an officer
- Officer surrounded or outnumbered
- Weapons present or discharged
- Sudden loss of communication during a volatile call
Once a 10-0 is declared, routine radio traffic is often restricted, and responding units may be authorized to proceed under emergency conditions.
Variations And Regional Interpretation
The meaning of 10-0 can vary slightly by jurisdiction. While many agencies define it strictly as an officer in distress, others broaden its use to include any critical emergency requiring immediate backup.
In some regions, similar emergencies may instead be communicated using codes such as 10-33 or 10-99, or replaced entirely with plain-language declarations depending on departmental policy.
Plain-Language Alternatives
Agencies that have moved away from coded language often replace 10-0 with direct statements such as:
- "Officer needs immediate assistance."
- "Officer in distress."
- "Emergency, send backup now."
These alternatives reduce the risk of misinterpretation during multi-agency responses and are often preferred during large-scale or inter-jurisdictional incidents.
Modern Relevance
Although many departments now emphasize plain-language communication, 10-0 remains deeply embedded in radio culture and training. Its brevity and emotional weight continue to make it instantly recognizable among experienced personnel.
Whether transmitted as a code or spoken plainly, the underlying purpose of 10-0 remains unchanged: to signal that an officer’s safety may be at risk and that immediate action is required.
Related 10-Codes
Codes frequently associated with 10-0 include 10-4 (acknowledgment), 10-8 (in service), 10-20 (location), and 10-33 (emergency traffic). Together, these codes help dispatchers and officers coordinate rapid responses during critical incidents.