I have a problem with the crc calculation for the preferred roaming list. Here is a roaming list from a motorola phone
Roaming List NAM 0: 00 31 30 39 00 02 40 03 10 51 c8 49 8c 6b b9 6a b0 74 d8 e1 b8 6e 14 a3 70 89 94 a3 02 5d 63 47 84 57 41 15 e0 0c 08 22 bc 81 02 2b 9c 0a 06 98 dd
The last two bytes are the 16 bit CRC-ccitt result for the message ahead. According to the protocol TIA-EIA-IS683A , the crc calcuation is described as follows:
Page 3-43 of IS683A
value 0xffff, am I correct ?
After I programmed like the protocol , I found the crc result is 0x6722 instead of 0x89dd. Also I tested on the website
which gave me the same result ( which means I am correct ? )
Now I am wondering whether it is possible they use a different algorithm to calculate the CRC of the preferred roaming list ? And I am wondering whether it matters if I use the protocol algorithm not their algorithm.