Common message header
| Common header | Common header | Common header | Common header | Common header | Data |
|---|---|---|---|---|---|
| Byte 0 | Byte 1 | Byte 2 | Byte 3 | Byte 4 | Variable |
| Type | Status | Battery | Temperature | ACK/Opt | Information |
Type: refer to Message types
Status:
| Bit | Status |
|---|---|
| Bit7-5 | Operating mode: 0- Standby/ 1- Motion tracking / 2- Permanent tracking / 3- Motion start/end tracking/ 4- Activity tracking / 5- OFF(2) |
| Bit 4 | Set if the user alert/SOS has been entered |
| Bit 3 | Reserved bit |
| Bit 2 | Set if the tracker is in motion state since the last payload is sent(1) |
| Bit 1 | Set for a periodic position message |
| Bit 0 | Set for a position on demand message |
Notes
(1)The tracker in in motion state until the expiration of motion_duration period. The motion bit setting can be pictured as follows:
(2)In shutdown payload, the operating mode is always OFF.
Battery: battery percentage (non encoded form)
- 0x00: the battery is charging (rechargeable devices only)
- 0x01 to 0x64: Battery percentage:
- Trackers with a rechargeable battery: the percentage reflects the actual value.
- Trackers with primary battery: the percentage is estimated based on the tracker usage.
- 0xFF: Error in measurement (rechargeable devices only)
Temperature: Temperature measured in the device, expressed in degree Celsius. Encoded form using lo= - 44, hi= 85, nbits= 8, nresv= 0. It is given with a step of 0.5°C
ACK/Opt:
| Bit | Parameter | Explanation |
|---|---|---|
| Bit 7-4 | ACK | Acknowledge token. Refer the section Acknowledge token for more details |
| Bit 3-0 | Opt | Optional data (depending on message type. Currently used only for position messages) |
Information: Variable part depending on the message type.