This Message 25 payload is used to acknowledge reception of the Addressed Text Message, Addressed TOI or Addressed Overlay (Message 26, FIDs 0-3). FID 2 shall always be transmitted after receipt of the complete Addressed Message.
|
Parameter |
Number of bits |
Description |
Encryption Status |
|
Function ID |
5 |
2 = Text message acknowledgement |
AES encrypted |
|
MMSI |
30 |
MMSI number of addressed message originator |
AES encrypted |
|
Type of Acknowledgement |
2 |
0 = Text Message 1 = TOI Message 2 = Overlay Message 3 = undefined |
AES encrypted |
|
Hour |
5 |
0-23 Hour of acknowledged message |
AES encrypted |
|
Minute |
6 |
0-59 Minute of acknowledged message |
AES encrypted |
|
Second |
6 |
0-59 Second of acknowledged message |
AES encrypted |
|
Hour |
5 |
0-23 Hour of this acknowledgement |
AES encrypted |
|
Minute |
6 |
0-59 Minute of this acknowledgement |
AES encrypted |
|
Second |
6 |
0-59 Second of this acknowledgement |
AES encrypted |
|
TOI Number |
20 |
TOI ID number assigned by designating unit; used for TOI acknowledgements only |
AES encrypted |
|
Overlay Number |
5 |
Overlay ID number assigned by originating unit; used for Overlay acknowledgements only |
AES encrypted |
|
Unused bits set to zero |
16 |
Unused bits set to zero. |
AES encrypted |
|
Checksum |
16 |
Cyclic Redundancy Check (CRC) 16-bit polynomial. |
AES encrypted |
|
TOTAL |
128 |
128 encrypted bits |
|
