Then I found this post:
I decided to give it go by downloading it from here:
I then proceeded to test it by key-in "reveng -w 16 -s 9876543210B283 01234567896282" in the shell to test for packet 9876543210B283 and 01234567896282 with xmodem.
I generate the CRC from here:
To run the program, simply open command prompt in the same directory as reveng.exe (I did it by Shift+Right Click in Windows).
The result is:
As you can see, RevEng successfully reverse engineered the given packets!
Many thanks to Mark Adler for introducing me to RevEng and Greg Cook for creating it!