Calculating FCS(CRC) for HDLC frame

Question

I have the following frame:

7e  01 00  00  01  00  18  ef  00  00  00   b5   20 c1 05 10 02 71 2e 1a c2 05 10 01 71 00 6e 87 02 00 01 42 71 2e 1a 01 96 27 be 27          


        

Answer 1

First of all, CRC value is 0xac93

Use this calculator: http://www.zorc.breitbandkatze.de/crc.html

• Set CRC order 16
• Polynomial 1021
• Initial value ffff
• Final value ffff
• "reverse data bytes"
• "reverse CRC result before Final XOR"

• Enter your sequence as:

  %01%00%00%01%00%18%ef%00%00%00%b5%20%c1%05%10%02%71%2e%1a%c2%05%10%01%71%00%6e%87%02%00%01%42%71%2e%1a%01%96%27%be%27%54%17%3d%b9
  

• Press "calculate" and you get 0xAC93