AIS message type
AIS message type 22: Channel management
A base station tells ships in a region which channels and power to use. What type 22 carries, who sends it, how often, and how to read it.
What type 22 is
Type 22 sets the channels, bandwidth and transmit power for an area, either as a rectangle or addressed to one or two ships. It is how a region can move AIS traffic away from the two default channels.
How to read it
Rare. A receiver tuned only to the two default channels will miss ships that have been moved elsewhere.
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 22.
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 |