In the complex world of law enforcement, communication is key. Police officers, dispatchers, and other emergency personnel rely on a specialized language of codes to relay information quickly, efficiently, and sometimes discretely. These codes, often referred to as “10-codes” or “signal codes,” have become an integral part of police operations across the globe.
While watching police dramas or listening to police scanners, you’ve likely heard phrases like “10-4” or “Code 3.” But what do these mysterious number combinations actually mean? Let’s delve into the fascinating world of police codes, exploring their origins, common examples, regional variations, and their evolution in modern policing.
The Origins of Police Codes
The development of police codes dates back to the early 20th century, coinciding with the widespread adoption of police radios. Before sophisticated digital communication systems, police radios operated on limited bandwidth, making brevity essential. Additionally, early radio transmissions were easily intercepted by civilians with basic radio equipment, creating a need for a level of privacy in police communications.
In 1937, the Association of Public-Safety Communications Officials (APCO) developed the first standardized set of codes, known as “Ten Signals” or “10-codes.” These codes were designed to represent common phrases and situations that officers encountered regularly, allowing for quicker and clearer radio communication.
What began as a practical solution to technical limitations has evolved into a rich tradition in law enforcement culture. Even with today’s advanced technology eliminating many of the original reasons for coded communication, police departments worldwide continue to use these shorthand systems.
Common Police Codes and Their Meanings
While codes can vary significantly between jurisdictions, some have achieved nearly universal recognition:
10-4: Perhaps the most famous police code, “10-4” simply means “message received” or “understood.” It’s the officer’s way of saying, “I hear you and understand your message.”
10-20: When an officer asks for someone’s “10-20,” they’re requesting their location. This is frequently used by dispatchers asking officers for their position or by officers asking dispatchers for the location of an incident.
10-27: This code requests a driver’s license check, commonly used during traffic stops.
10-32: This typically indicates a person with a gun, alerting responding officers to a potentially dangerous situation.
10-99: Often used to indicate a wanted or dangerous person, this code puts officers on high alert.
Code 3: While not a 10-code, “Code 3” generally means respond with lights and sirens, indicating an emergency response is needed.
Signal 13: In many jurisdictions, this is an officer’s call for immediate assistance—essentially a “officer needs help” alert that mobilizes all available units to respond.
Regional Variations in Police Codes
One of the most fascinating aspects of police codes is their remarkable variation between different agencies and geographical regions. What means “traffic stop” in one city might indicate “bomb threat” in another. This lack of standardization has occasionally led to confusion when multiple agencies respond to the same incident.
For example, in the Los Angeles Police Department:
- “Code 2” means respond urgently without lights and sirens
- “Code 4” indicates “no further assistance needed”
- “Code 7” means an officer is taking a meal break
Meanwhile, in New York City:
- “10-13” is the emergency call for an officer needing assistance
- “10-85” requests additional units
- “10-98” indicates an officer has completed an assignment
Some departments have developed unique systems entirely separate from the 10-code framework. The California Highway Patrol, for instance, uses “11-99” to indicate an officer needs emergency assistance, while their “11-80” refers to a major traffic accident with injuries.
These regional differences reflect the organic way these codes developed over decades, with each department adapting and creating codes that addressed their specific needs and common situations.
Plain Language Movement in Modern Policing
After the September 11, 2001 terrorist attacks, the limitations of non-standardized code systems became painfully apparent. When multiple agencies from different jurisdictions responded to the World Trade Center and Pentagon, communication difficulties arose partly due to conflicting code systems.
This led to the “plain language movement” in emergency services. The Federal Emergency Management Agency (FEMA) began advocating for the use of clear, common language rather than codes during multi-agency responses and major disasters.
The Department of Homeland Security’s National Incident Management System (NIMS) now strongly recommends that emergency responders use “plain language” rather than codes, especially during incidents requiring multi-agency coordination.
Despite this push, many departments maintain their traditional code systems for day-to-day operations, reserving plain language for multi-agency responses. As one veteran officer put it, “Old habits die hard in police work.”
The Digital Evolution of Police Communication
Modern police communication has evolved far beyond simple radio codes. Computer-aided dispatch systems, mobile data terminals in patrol vehicles, and encrypted digital radio networks have transformed how officers communicate.
Many departments now use sophisticated text-based messaging systems that allow officers to receive detailed information without radio transmission. Some jurisdictions have even developed smartphone applications that provide secure communication channels between officers.
Despite these technological advances, voice communication remains essential in emergency situations, and the efficiency of code systems continues to prove valuable. As one police communications expert noted, “In a crisis, when seconds count, saying ’10-32′ is still faster than saying ‘person with a gun’.”
Why Police Codes Endure
The persistence of police codes in an era of advanced communication technology speaks to their practical benefits and cultural significance within law enforcement. These codes serve several purposes beyond their original intent:
- Efficiency: Codes allow complex concepts to be communicated quickly and clearly.
- Officer safety: In some situations, codes provide a measure of discretion when civilians might be listening.
- Tradition and identity: The specialized language helps create a sense of shared identity among law enforcement professionals.
- Emotional distance: Using codes for traumatic situations (like “Signal 7” for a dead body) can help officers maintain professional detachment.
Whether you’re a crime drama enthusiast, a citizen interested in understanding police operations, or someone considering a career in law enforcement, understanding these codes offers a window into the unique culture and operational realities of policing.
While technology continues to transform police communication, the legacy of these efficient numerical shorthand systems remains firmly embedded in law enforcement culture. As one police captain reflected, “The codes might change, but the need to communicate quickly and clearly never will.”