Why Does "12" Mean Police? A History of Police Radio Codes

As a tech geek and data analyst who loves streaming, gaming, and all things digital, I’m fascinated by the evolution of specialized languages and codes used by different groups. Police radio codes are a classic example that many people recognize, even if they don’t know the origins. So why does “12” mean police? The story behind this numerical code provides a glimpse into the development of policing communications over the past century.

The Rise of Police Radio Systems

It’s hard to imagine effective policing without instant radio communication between officers and dispatchers today. But radio tech was just emerging in the early 20th century. In 1921, the Detroit Police Department worked with Detroit News radio station WWJ to experiment with installing radio receivers in patrol vehicles. Officers could call the station to report crimes and request backup, though they didn’t have transmitters yet in the cars.

By 1928, one-way police radio systems with receivers in cars and central transmitters at HQ were operating in Detroit, Bayonne, NJ and Yonkers, NY. Officers had to drive to call boxes around the city to make reports back to dispatchers monitoring the radio desk.

Two-way radio systems that allowed both transmission and reception finally arrived in the 1930s, overcoming the limitations of one-way communication. This breakthrough meant officers could communicate emergencies in real-time from their vehicles. Adoption spread quickly, with by 1942 an estimated 80% of police departments serving populations over 10,000 using two-way radio.

The “10” Radio Codes are Born

Efficient radio communication required development of procedures and shorthand codes. Charles “Charlie” Hopper, communications director for the Illinois State Police, established one of the first systems to go beyond basic letter-based codes.

Between 1937-40, Hopper compiled a list of over 100 numbered codes with associated meanings as part of a standardized “10-code” system. This two-digit structure allowed for many condensed radio call signals. The Illinois State Police implemented Hopper’s 10-codes on their radio network in 1941.

The 10-code system gained popularity across police departments and emergency services nationally over the following decades. By 1959, the Association of Public-Safety Communications Officials (APCO) published the first official guide to APCO 10-codes as a model for agencies, although regional variations persisted.

Here’s a snapshot of common 10-codes and meanings adopted from Hopper’s original codes:

This table shows how Hopper‘s 10-code system allowed police and dispatchers to communicate key information succinctly over radio. The codes evolved over time but provided core police shorthand starting in the 1930s-40s.

“10-12” Enters the Lexicon

Among Hopper’s original codes was 10-12, meaning “Visitors are present, or civilian is present.” This warned officers arriving on a scene that they may encounter bystanders or other civilians.

While 10-4 and 10-20 became widely used in their own right, 10-12 specifically seemed to gain traction in the state of Georgia. By the 1960s, officers in Atlanta shortened 10-12 to “12” in radio chatter and internal slang when referring to the police or additional officers showing up.

For example, they might say, “12 is en route” instead of “10-12 is en route.” This evolution from the 10-12 code to the shorthand 12 was an early indicator of how police codes permeated into broader culture and language.

Going “10-7” for Lunch

I still get a kick out of kids today using the slang “I’m going 10-7” when they’re heading to lunch. 10-codes have become so ingrained that many people don’t even realize they originated from police radio! 10-7 is police speak for being “out of service” for a meal or personal break.

Other codes like 10-4 for “affirmative” and the all-clear “all 10-4” that migrated into general CB radio lingo show how police communication conventions became part of popular culture.

Some codes like 10-66 (“all units stand by”) and 10-78 (“request assistance”) rarely made the leap into public vernacular. But the widespread public scanner listening culture through the ‘60s-‘90s resulted in many common police terms and codes entering mainstream consciousness.

The Scanner Subculture

Starting in the 1960s and through the CB radio craze of the 1970s, average citizens could listen in on police and emergency radio traffic with affordable scanners. A whole subculture emerged around monitoring police band frequencies and compiling directories of agency-specific codes.

By the mid-1990s, over two million Americans were estimated to listen regularly to police and public service scanner traffic. The rise of online forums in the 2000s spawned endless chatter dissecting police codes and procedures among radio hobbyists.

Various efforts emerged to unify police communication codes, like APCO’s guidelines for standard 10-codes. But inconsistencies remain today, with local codes evolving based on community needs and customs. Metro Atlanta in particular developed a diverse system of specialized 10-codes from the basic templates.

Going “Are you 10-12?”

With the advent of cell phones, use of 10-codes has diminished over the past couple decades. Dispatchers are more likely to speak plain English rather than coded numbers that could be misconstrued. But many codes persist in the background of police culture and language.

The evolution of “10-12” into the casual slang of “12” endured as a simple shorthand for referring to other officers or the police force. In Atlanta, it’s still common to hear cops ask each other conversationally if they are “10-12” before explaining a situation, as if to verify the other is a fellow officer.

Others like “10-100” indicating bathroom break and the catch-all “10-24” for additional information demonstrate how ingrained some codes remain day to day. Many officers still find the terse 10-code style efficient for rapid communication.

WhenCodes Go Public

Police codes occasionally grab public attention when misunderstood comments get captured on scanners or go viral, often during high profile local incidents. Take the case of the 2002 DC sniper attacks. A poorly phrased radio comment about white box trucks fueled public panic, as listeners lacked the full context.

Similar confusion surrounded Connecticut State Police codes during the 2012 Sandy Hook shooting tragedy. Use of specialized internal codes for officer down and other grave scenarios caused widespread confusion.

These examples illuminate how reliance on numbers and codes unknown to the public can backfire without proper explanation. They highlight the need for transparent public communication especially during crises, even as codes remain useful for police coordination.

Law Enforcement Communication Today

While some activists have called for eliminating coded communication to increase police transparency, codes remain an important tool for officers. Security concerns limit publicizing the full details of all internal police radio terminology.

However, departments balance this by having dispatchers communicate in plain speech, especially when the public may be listening in times of danger or unrest. Codes endure as useful shorthand internally between officers to call for routine backup or signal “all clear.”

Modern police communication integrates coded radio transmissions with live public information. The story of how “10-12” became the slang “12” for police illustrates the interplay between internal jargon and public understanding. Breaking down this history makes officers seem more human while appreciating their need for efficient codes.

So next time you see “12” used to reference police or hear an officer say “10-4”, you can smile knowing the origins of this numerical “language” adopted by law enforcement over the past century. The codes that developed from necessity and progressed into cultural tropes provide a fascinating look at the evolution of technology intersecting with policing over decades. As both a tech nerd and average citizen, digging into this sliver of American linguistic history gives me perspective on the human side of police work.