AIS message type
AIS message type 7: Binary acknowledge
Confirms receipt of up to four type 6 messages. What type 7 carries, who sends it, how often, and how to read it.
What type 7 is
Type 7 is the receipt for an addressed binary message. It lists the MMSIs of up to four stations whose type 6 messages are being acknowledged, with their sequence numbers.
How to read it
Pure protocol traffic. It never carries a position.
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 7.
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 |