10-4: Acknowledgment | Affirmative

In APCO 10-codes, 10-4 means "Acknowledgment" or "Affirmative."

It is one of the most widely recognized 10-codes and is used to confirm that a message has been received and understood. For example, if a dispatcher gives an instruction or provides information, the responding officer can reply with 10-4 to indicate that the message was received:

10-3: Stop Transmitting | Cease Transmission

In APCO 10-codes, 10-3 means "Stop Transmitting" or "Cease Transmission."

It is used to instruct others to stop communicating temporarily, often because the radio frequency needs to be kept clear for important or emergency traffic. For example, in a situation where critical communication needs to occur without interference, a dispatcher or a commanding officer might issue a 10-3 to stop any non-essential transmissions:

10-2: Signal Good

In APCO 10-codes, 10-2 typically means "Signal Good" or "Receiving Well." This is the opposite of 10-1 and is used to indicate that radio communications are clear and strong.

Here’s an example of how it could be used in a communication exchange:

10-0: Beware | Caution

In APCO (Association of Public-Safety Communications Officials) 10-codes, which are used primarily by law enforcement and emergency services, the code 10-0 typically means Use Caution or Danger/Caution. It serves as a quick, standardized communication to alert officers or emergency responders that they may be entering a situation that is potentially dangerous, requiring heightened awareness or a cautious approach.

10 Codes: APCO Code

10-codes are standardized radio communication codes commonly used by law enforcement and emergency services to convey information quickly and clearly. /* === BASE ACCORDION === */ .apco-accordion { max-width: 960px; margin: 2rem auto; } .apco-group { margin-bottom: 0.75rem; border-radius: 8px; overflow: hidden; background: #1f1f1f; } .apco-group summary { list-style

HTTP Status Codes

HTTP Status Codes are standardized three-digit numbers returned by a web server to indicate the result of a client’s request. Introduced with the HTTP/1.0 specification in 1996, they categorize responses into five classes: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), and 5xx (server error). For example, 200 OK signals a successful request, 404 Not Found indicates a missing resource, and 500 Internal Server Error reflects server-side failure.