AIS message type
AIS message type 12: Addressed safety related message
A short free-text safety message sent to one station. What type 12 carries, who sends it, how often, and how to read it.
What type 12 is
Type 12 carries up to 156 characters of six-bit text to a single destination MMSI. It is used for safety-related text such as an urgent notice from a coast station or another ship.
How to read it
Six-bit text is upper case only. It is a text message, not a substitute for a voice call on VHF or DSC.
Decoding it
The AIS message decoder reads the message type and sender MMSI of any sentence, including this one, but does not unpack the body of type 12.
All message types
| Type | Name |
|---|---|
| 1 | Position report, scheduled (Class A) |
| 2 | Position report, assigned schedule (Class A) |
| 3 | Position report, response to interrogation (Class A) |
| 4 | Base station report |
| 5 | Static and voyage related data (Class A) |
| 6 | Binary addressed message |
| 7 | Binary acknowledge |
| 8 | Binary broadcast message |
| 9 | Standard SAR aircraft position report |
| 10 | UTC and date inquiry |
| 11 | UTC and date response |
| 12 | Addressed safety related message |
| 13 | Safety related acknowledgement |
| 14 | Safety related broadcast message |
| 15 | Interrogation |
| 16 | Assignment mode command |
| 17 | DGNSS broadcast binary message |
| 18 | Standard Class B equipment position report |
| 19 | Extended Class B equipment position report |
| 20 | Data link management message |
| 21 | Aid-to-navigation report |
| 22 | Channel management |
| 23 | Group assignment command |
| 24 | Static data report (Class B) |
| 25 | Single slot binary message |
| 26 | Multiple slot binary message with communications state |
| 27 | Long-range AIS broadcast message |