1. Break
 Every LIN frame begins with the break, which comprises 13 dominant bits (nominal) followed by a break delimiter of one bit (nominal) recessive. This serves as a start-of-frame notice to all nodes on the bus.
2. Sync
The sync field is the second field transmitted by the master task in the header. The sync field allows slave devices that perform automatic baud rate detection to measure the period of the baud rate and adjust their internal baud rates to synchronize with the bus.
3. ID
The ID field is the final field transmitted by the master task in the header. This field provides identification for each message on the network and ultimately determines which nodes in the network receive or respond to each transmission. All slave tasks continually listen for ID fields, verify their parities, and determine if they are publishers or subscribers for this particular identifier. The LIN bus provides a total of 64 IDs. IDs 0 to 59 are used for signal-carrying (data) frames, 60 and 61 are used to carry diagnostic data, 62 is reserved for user-defined extensions, and 63 is reserved for future protocol enhancements. The ID is transmitted over the bus as one protected ID byte, with the lower six bits containing the raw ID and the upper two bits containing the parity.