Crccalc.com lists the initial state of the CRC as 0xB2AA, whereas we use the initial value of 0x554D, the bit reversed value. This value is the one that gives the correct result (matching crccalc.com's check) when run with our code, and it is also the value given in the specification at https://networkupstools.org/protocols/riello/PSGPSER-0104.pdf