| Preamble | 0xFF | 1 byte |
| Destination | 1 byte | |
| Source | 1 byte | |
| Length | No. of message bytes | 4 bits (lower - upper 4 reserved) |
| Checksum A | ADD message bytes | 1 byte |
| Checksum B | XOR message bytes | 1 byte |
| TTL | Must start > no of chips | 1 byte |
| Header checksum | XOR header | 1 byte |
| Message | First byte command only 16 bytes | |