The CRC calculated problems

marty 2005-08-04 04:20:55 No: 58541

I have a question regarding the CRC on NEC level 2B protocol,  following informations were known so far :

1.The CRC polynomial ( CRC-CCITT ) : X16+X12+X5+1

2. Data Format : JIS 7 and ODD parity

3. CRC calculation range : First Byte after "STX" until the "ETX"(included)

The datatraces from NEC host send to printer

02 31 A4 8F 8A 20 20 20 20 20 20 20 20 20 20 31 8A 83 69 C7 FF FF
  |------------------------crc calculated range------|

02:STX ,  31:UA address  , A4: SA address  ,  83 :ETX   , CRC : 69 C7

My problem is the CRC values(69 C7) in the datatraces never matched my calculated result.
Please refer this web site to calculated : http://www.lammertbies.nl/comm/info/crc-calculation.html

I hope to take some helpful information from here and thank for everybody