Solution
USB-8506 is using the NXP TJA1028 LIN transceiver which supports baud rates up to 20 kbit/s.
The TJA1028 LIN transceiver specification can be seen here(
External Link: LIN transceiver with integrated voltage regulator)
. From this transceiver specification sheet page 8, the baud rates from 2.4 kBd up to 20 kBd and is LIN 2.0/LIN 2.1/SAE J2602 compliant. Thus, the Min Baud Rate would be 2.4kBd.