CRC error calculation?

Mohit2 years ago

I try CRC error calculation as per in given pdf.

https://www.traccar.org/protocol/5023-gt06/Benway%20Protocol.pdf

with
login_buffer :- 0x78 0x78 0x0D 0x01 0x01 0x23 0x45 0x67 0x89 0x01 0x23 0x45 0x00 0x01 0x8C 0xDD 0x0D 0x0A
with length = 18

i dont know how i get 0x8C 0xDD as a CRC error using code example in above pdf.