In APCO, Association of Public-Safety Communications Officials 10-codes, 10-5 means "Relay Message" or "Relay To". It is used to indicate that a message should be passed through another unit, officer, or dispatcher to reach its intended recipient.
Here’s how it might be used in a real-world scenario:
- Dispatch: "Unit 12, 10-5 to Unit 34. Relay the suspect description."
- Officer: "Copy 10-5, will relay to Unit 34."
In this exchange, 10-5 directs a unit to pass along critical information through the radio network. This ensures that messages reach the correct personnel efficiently, especially when direct communication is not possible.
Historical Background
The 10-5 code was developed as part of the original APCO 10-code system to streamline communications in an era when radio channels were limited and bandwidth was constrained. Early public-safety operations often relied on intermediary units to relay messages between officers, patrol vehicles, and dispatch centers.
By standardizing a numeric command like 10-5, agencies could reduce repetition, avoid misunderstandings, and maintain clarity on busy frequencies, particularly during large-scale operations or emergencies.
Operational Usage
In practice, 10-5 is commonly used when direct communication with a specific unit is not possible or practical. The unit receiving the 10-5 instruction becomes responsible for ensuring the message is accurately transmitted to the intended recipient.
Typical scenarios include:
- Passing information from dispatch to a unit out of direct range
- Relaying suspect or vehicle descriptions between units
- Forwarding updates during multi-agency incidents
- Maintaining communication during signal interruptions or congestion
Using 10-5 helps reduce errors that can occur when multiple units are attempting to communicate simultaneously on the same channel.
Variations And Regional Interpretation
While 10-5 generally indicates “relay message,” some agencies may use it more broadly to include passing updates, instructions, or reports. Others may prefer plain-language alternatives or different codes depending on local protocol.
Because 10-codes were developed locally rather than nationally, slight differences in interpretation can exist between neighboring departments or during multi-agency operations.
Plain-Language Alternatives
Agencies favoring plain-language communication may replace 10-5 with phrases such as:
- "Please relay this message to Unit 34."
- "Forward this information to the intended unit."
- "Pass this on to the relevant officer."
These alternatives improve clarity and reduce the risk of miscommunication when multiple agencies are responding simultaneously.
Modern Relevance
Although some departments have moved toward plain-language radio traffic, 10-5 remains in use due to its brevity and efficiency. It continues to be taught in training programs and used in both formal and informal communications.
Whether communicated as a code or spoken plainly, the purpose of 10-5 remains the same: to ensure that messages are accurately relayed through the appropriate channels without delay.
Related 10-Codes
Codes commonly associated with 10-5 include 10-4 (acknowledgment), 10-8 (in service), 10-12 (stand by / visitors present), and 10-20 (location). Together, these codes help ensure that messages flow efficiently, accurately, and clearly across the radio network.