In APCO, Association of Public-Safety Communications Officials 10-codes, 10-21 means "Call By Telephone" or "Telephone Message". It is used to request that an officer, unit, or dispatch relay information via phone rather than radio, often for privacy, clarity, or administrative purposes.
Here’s how it might be used in a real-world scenario:
- Dispatch: "Unit 32, 10-21 the reporting party for additional details."
- Officer: "10-21, calling now."
In this exchange, the officer acknowledges the request to contact the complainant or another party by phone. The use of 10-21 ensures that radio traffic remains clear while allowing important information to be communicated securely.
Operational Purpose
10-21 is commonly used for follow-up communications, routine inquiries, or situations where details are too lengthy or sensitive to be transmitted over radio. It helps maintain operational efficiency and supports confidentiality when handling reports, tips, or administrative matters.
Dispatch can track which units are engaged in a 10-21 task to manage workload and unit availability effectively.
Officer Safety And Communication Efficiency
Using 10-21 reduces radio congestion, allowing other units to handle urgent calls without interference. Officers may temporarily advise 10-6 (busy) while making telephone contact, then confirm completion with 10-4 (acknowledgment) when finished.
Variations And Agency Practices
Some agencies use 10-21 strictly for contacting complainants or witnesses, while others apply it broadly for any situation requiring telephone communication. Local protocol may dictate whether follow-up information is logged in the dispatch system or reported back over radio after the call.
Plain-Language Alternatives
Agencies emphasizing plain-language communication may replace 10-21 with phrases such as:
- "Call the reporting party."
- "Relay message by phone."
- "Contact by telephone."
Related 10-Codes
Codes commonly associated with 10-21 include 10-4 (acknowledgment), 10-6 (busy), 10-8 (in service), 10-14 (information), and 10-20 (location). Together, these codes ensure clear, tracked, and effective communication while supporting both operational efficiency and officer safety.