| Letter | APCO | ICAO |
| A | Adam | Alfa |
| B | Boy | Bravo |
| C | Charles | Charlie |
| D | David | Delta |
| E | Edward | Echo |
| F | Frank | Foxtrot |
| G | George | Golf |
| H | Henry | Hotel |
| I | Ida | India |
| J | John | Juliett |
| K | King | Kilo |
| L | Lincoln | Lima |
| M | Mary | Mike |
| N | Nora | November |
| O | Ocean | Oscar |
| P | Paul | Papa |
| Q | Queen | Quebec |
| R | Robert | Romeo |
| S | Sam | Sierra |
| T | Tom | Tango |
| U | Union | Uniform |
| V | Victor | Victor |
| W | William | Whiskey |
| X | X-ray | X-ray |
| Y | Young | Yankee |
| Z | Zebra | Zulu |
Association of Public-Safety Communications Officials-International (APCO) was founded in 1935. It is the world's oldest and largest organization of public safety communications professionals and supports the largest U.S. membership base of any public safety association. APCO's mission is to be a leader in providing public safety communications expertise, professional development, technical assistance, advocacy and outreach to benefit its members and the public.
The International Civil Aviation Organization (ICAO) is a UN specialized agency, established by States in 1944 to manage the administration and governance of the Convention on International Civil Aviation (Chicago Convention).