| 41 | Navigation, searching equipment |
| 412 | Decca, loran, omega, radio direction finder |
| 42 | Communication equipment |
| 421 | Radio plant, gmdss |
| 422 | Lifeboat radio transmitters, epirbs |
| 423 | Data transmission plants, communication |
| 424 | Vhf/uhf telephones |
| 425 | Calling/command/crew call telephone plants, walkie-talkies |