If you have ever listened to a police scanner, watched a crime drama, or played a law enforcement video game, you have likely heard a flurry of numbers exchanged over the radio. Phrases like “10-4,” “10-20,” and “10-8” are the heartbeat of police communication. While “10-4” has crossed over into everyday slang to mean “okay,” other codes remain a mystery to the general public.
One of the most frequently used signals in law enforcement is 10-8. It is a fundamental status update that dictates the flow of patrol work and resource management. When a dispatcher hears this code, they know exactly where an officer stands in their shift and what they can handle next.
Understanding these codes offers a fascinating glimpse into how first responders operate. It reveals a language built on brevity, clarity, and safety. This guide breaks down exactly what 10-8 means, how it fits into the lifecycle of a police call, and why these numbers were invented in the first place.
The Definition of 10-8
In the vast majority of police departments across the United States, Code 10-8 means “In Service” or “Available for Assignment.”
When an officer radios that they are 10-8 (often pronounced “ten-eight”), they are telling dispatch that they are active, in their patrol vehicle, and ready to respond to a call. It is the default status for a patrol officer who is not currently occupied with a suspect, a report, or a break.
Think of it as the “Green Light” of policing. Until an officer declares themselves 10-8, the dispatch center assumes they are busy and cannot send them to help a citizen calling 911.
The Opposite: Code 10-7
To fully understand 10-8, it helps to know its counterpart. Code 10-7 typically means “Out of Service.”
An officer might go 10-7 for several reasons:
- 10-7 OD: Off Duty (ending their shift).
- 10-7 at the Station: Booking a prisoner or filing paperwork.
- 10-7 for Lunch: Taking a meal break.
The patrol shift is essentially a constant toggle between 10-8 (ready to work) and 10-7 (unavailable).
The Lifecycle of a Call
To see 10-8 in action, it helps to look at the timeline of a typical police incident. Officers use codes to timestamp every movement they make. This ensures there is a permanent record of their location and status for safety and legal reasons.
Here is how a standard traffic stop might sound over the radio:
- Initiating the Stop: The officer observes a speeding car. They radio dispatch to say they are stopping a vehicle. They might use a code like 10-38 (Stopping Suspicious Vehicle). At this moment, they are no longer available.
- Investigation: The officer runs the license plate and speaks to the driver. They are occupied and cannot take other calls.
- Resolution: The officer issues a citation or a warning.
- Clearing the Scene: As the officer gets back into their cruiser and the driver pulls away, the officer picks up the mic and says, “Show me 10-8.”
That final transmission alerts the dispatcher that the officer is back on the hunt and available to take the next pending call in the queue.
Why Do Police Use 10-Codes?
You might wonder why officers don’t just say “I’m ready” or “I’m available.” The origin of the “10-code” system dates back to the late 1930s, and it was born out of technological necessity.
Cutting Through the Static
In the early days of police radio, the technology was primitive. Vacuum tube radios took time to “warm up” after the push-to-talk button was pressed. If an officer started speaking immediately, the first syllable of their sentence was often cut off.
Charles Hopper, a communications director for the Illinois State Police, developed the Ten-Signals in 1937 to solve this. By starting every transmission with “Ten,” it ensured that the radio had time to transmit the second, more important number. Even if the “Ten” was clipped by static or lag, the “Eight” would come through clearly.
Brevity and Privacy
Radio bandwidth is a precious resource. During a major emergency, dozens of officers might need to speak on a single channel. Codes compress complex sentences into split-second transmissions. Saying “10-8” is significantly faster than saying “I have finished my traffic stop and I am now ready for another call.”
Historically, codes also offered a thin layer of privacy. While anyone with a scanner could listen in, the average citizen didn’t know that a “10-50” meant a traffic accident or that a “10-32” meant a person with a gun.
Are 10-Codes Still Used Everywhere?
While 10-8 is widely recognized, the era of strictly using 10-codes is fading. The Department of Homeland Security and the Federal Emergency Management Agency (FEMA) have actually discouraged their use in recent years.
The turning point was September 11, 2001. During the attacks, police and fire departments from different jurisdictions rushed to the scene. However, because different agencies used different codes for the same events, communication broke down. One department’s code for “help needed” was another department’s code for “situation under control.”
To prevent these dangerous misunderstandings, the National Incident Management System (NIMS) now recommends “Plain Language.”
The Shift to Plain English
Many modern departments have dropped the codes entirely. Instead of saying “10-8,” they simply say “Available.” Instead of “10-23,” they say “On scene.”
However, old habits die hard. 10-8 is so deeply ingrained in police culture that even agencies with “Plain Language” policies still use it colloquially. It remains one of the few codes, alongside 10-4, that is considered nearly universal across the United States.
Other Common Codes You Might Hear
If you are tuning into a local scanner app or trying to decipher a news report, here are a few other common codes that often accompany 10-8:
- 10-4: Message received / Affirmative.
- 10-9: Repeat last transmission (usually because of static).
- 10-20: Location (e.g., “What is your 10-20?”).
- 10-23: Arrived at the scene.
- 10-33: Emergency / Officer needs assistance immediately.
Note: While 10-8 is standard, codes for specific crimes (like burglary or assault) vary wildly between states and counties.
Frequently Asked Questions
Is Code 10-8 the same for firefighters and EMS?
Often, yes. Many fire departments and ambulance services adopted the police 10-code system for interoperability. For a paramedic, 10-8 usually means they have dropped off a patient at the hospital and are ready for the next medical emergency.
Can a civilian use 10-8?
While you can use it, it is mostly restricted to professional radio use. However, truckers and CB radio enthusiasts adopted the 10-codes in the 1970s. You might hear truck drivers use 10-8 to indicate they are back on the road after a rest stop.
Does 10-8 imply the situation is resolved safely?
Indirectly, yes. If an officer goes 10-8, it means the previous incident has been handled. If the situation were still dangerous or active, the officer would remain on the scene. Going 10-8 signals a return to normalcy.
Staying Tuned In
Police radio codes are more than just numbers; they are a shorthand for the dangerous, fast-paced work of law enforcement. Code 10-8 represents the backbone of police coverage. It is the signal that help is available and that the officer is ready to serve.
While the push for “Plain English” continues to modernize radio traffic, the legacy of the 10-code system remains strong. The next time you hear “Unit 12, show me 10-8” on a TV show or a scanner, you’ll know exactly what it means: the job is done, and the patrol continues.