LIN Terminology

Master Process
The first part of a LIN transaction, which contains the header and is followed by a response period where it waits for slave processes.
Slave Process
The second part of a LIN transaction, in which data is transmitted on the bus followed by a checksum. The device that initiates the master process may also be the one that performs the slave process.
Header
The primary section of the master process, which contains the Break, Delimiter bit, Sync Field, and PID byte.
Response
The section of the LIN transaction in which the master process relinquishes the bus and one or more slave processes transmit data.
Break
The start of a transaction, at least 13 dominant bits in a row, followed by a delimiter.
Delimiter
The separation between the break and sync fields consisting of at least one recessive bit.
Sync
The character following the Break and Delimiter bits, consisting of the value 0x55, which synchronizes the transmission rate between the master and the slaves.
PID/Identifier
The last piece of the header. This contains information about whether the master expects to send or receive data, how much data is to be sent/received, and which slave(s) will be communicated with. What each individual identifier means differs for each LIN network, and these definitions are outlined in a LIN Description File (LDF). The identifier also includes two Parity bits.
VBAT
Battery voltage of the vehicle. VSUP is derived from this voltage.
VSUP
Primary voltage of the ECU and LIN transceivers. This can differ from VBAT due to protection circuitry between the battery and the actual components.
LDF
The LIN Description File, an ASCII document that contains detailed information of a LIN bus, including the nodes on the bus, the signals, and the frames that will be sent on the bus and their meanings.