Check CRC

[syssi]

const packet = Buffer.from('FF551103310000000001', 'hex');

const payload = packet.slice(2, -1);
// "11033100000000" (hex string)

const checksum = payload.reduce((acc, item) => (acc + item) & 0xff, 0) ^ 0x44;
// checksum: 0x01

packet[packet.length - 1] == checksum;
// returns true