| Packet ID | Size | Data |
| 01 | 14 | PTU |
| 02 | 18 | GPS |
| 03 | Variable | External instrument (see table below) |
| 04 | 20 | Extended PTU |
| 05 | 30 | Extended GPS |
External instrument packets :
| Instrument ID range | Size | Instrument type |
| 01 - 07 (hex: 01-07) | 13 | ECC ozone sonde |
| 08 - 15 (hex: 08-0F) | 17 | Cryogenic frostpoint hygrometer (CFH) |
| 24 - 31 (hex: 18-1F) | 25 | Cobald backscatter sonde |