I have come across this decode data from what is exchanged between vehicle and EVSE im sure its probably on the forum somewhere but i thought i would add it again just incase.
Hope this helps

Table F.3 – The physical/data link layer specifications for system A
Communication protocol ISO 11898-1 and ISO 11898-2 The extension bit (12 − 29 bit) is not used.
Transmission rate (kbps) 500
Cycle 100 ms ± 10 %