Police code 10-42 means an officer is ending their tour of duty. When transmitted over the radio, it tells dispatch the officer is done for the day and no longer available for calls. The same code carries a second, heavier use: at ceremonies for retiring officers and those killed in the line of duty, a final 10-42 broadcast marks the permanent end of a law enforcement career.
“Ending Tour of Duty” on Daily Radio Traffic
In the standardized ten-code system used by law enforcement, 10-42 signals the end of a shift. It pairs with 10-41, which marks the beginning of a tour. Together the two codes bracket an officer’s working hours so dispatch always knows who is available.
The exchange itself is brief. An officer keys the radio, states their unit number, and transmits the 10-42 code. Most departments require the officer to include their final location, usually the station parking lot or a substation. The dispatcher repeats the unit number, acknowledges the code, and records the exact time in the department’s Computer-Aided Dispatch system.
In agencies where patrol cars are shared between shifts, the outgoing officer leaves keys for the next crew. Where take-home vehicles are permitted, officers follow department policies about keeping the car within a certain distance of their jurisdiction. A clean handoff keeps response coverage tight during shift changes, which is when gaps are most likely to appear.
Why the Timestamp Matters
The CAD entry created at 10-42 is more than a radio formality. It becomes a time-stamped legal record showing precisely when the officer went off-duty, information that can matter in court if questions arise about where an officer was during an earlier incident.
The same timestamp feeds staffing records that command staff use to track how many officers are on patrol at any given moment, and it becomes part of the officer’s payroll documentation. The national median hourly wage for police and sheriff’s patrol officers was $34.75 as of the most recent federal data, so accurate shift records directly affect compensation.1Bureau of Labor Statistics. Police and Sheriff’s Patrol Officers – Occupational Employment and Wage Statistics
Overtime is where the timestamp carries the most weight. Law enforcement employees operate under a different overtime structure than most workers. Rather than the standard 40-hour weekly threshold, agencies can use a 28-day work period in which overtime kicks in only after 171 hours for law enforcement personnel.2Office of the Law Revision Counsel. 29 USC 207 – Maximum Hours Accurate 10-42 timestamps directly affect those calculations at the end of each work period.
Whether Your Department Still Uses It
Not every department still uses 10-42, or any ten-code at all. After Hurricane Katrina in 2005 exposed serious communication breakdowns between agencies using different code systems, the federal government pushed for plain language in emergency communications. The National Incident Management System now requires plain language during multi-agency, multi-jurisdiction events like major disasters and large-scale exercises.3Federal Emergency Management Agency. NIMS Alert 06-09 – NIMS and Use of Plain Language
An important distinction often gets lost here. NIMS does not require agencies to abandon ten-codes for everyday internal operations. Starting in fiscal year 2006, federal preparedness grant funding was tied to using plain language during incidents that involve responders from other agencies, but daily ten-code use did not affect an agency’s grant eligibility.3Federal Emergency Management Agency. NIMS Alert 06-09 – NIMS and Use of Plain Language
In practice, many departments have moved to plain language for everything. Others keep ten-codes internally and switch to plain talk during joint operations. Some agencies have adopted entirely different systems, like status buttons on in-car mobile data terminals, where an officer taps a screen to go off-duty rather than making a voice transmission at all. The specific meaning of any given numeric code can also vary by region, so an officer transferring between agencies may find the new department uses a completely different communication vocabulary.
End of Watch: The Ceremonial 10-42
Outside daily operations, 10-42 carries a weight no other code in the system comes close to matching. The phrase “End of Watch” has become synonymous with the code itself, and it marks two of the most significant moments in law enforcement culture: retirement and death in the line of duty.
Retirement Ceremonies
When an officer retires, many departments hold a final radio call. A dispatcher contacts the retiring officer’s unit number one last time, acknowledges their years of service, and announces that the officer is permanently out of service as of that date and time. The officer responds, the dispatcher closes with the 10-42 code, and the career is formally over. The exchange usually lasts less than a minute, but anyone who has heard one knows the silence that follows carries decades of meaning.
Fallen Officer Memorials
The most solemn use of 10-42 comes when an officer dies in the line of duty. During the “Last Call” ceremony, a dispatcher broadcasts across all radio channels, calling the fallen officer’s unit number and requesting a response. After a pause with no answer, the dispatcher calls again. When silence is the only reply, the dispatcher announces that the officer is 10-42 for the final time, permanently end of watch. The recording of that broadcast is often given to the officer’s family.
The toll behind those ceremonies is not abstract. In 2025 alone, 111 federal, state, county, and municipal officers died in the line of duty across the United States. The National Law Enforcement Officers Memorial in Washington, D.C. now bears more than 24,400 names. Each of those names received a final 10-42, a tradition that gives the code a permanence far beyond its original purpose as a shift-end shorthand.