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  }
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CRC (Cyclic Redundancy Check) is an error-detecting code using for detect accidental changes to RAW data. The algorithm how to calculate CRC-16 (also known as CRC-16/IBM) you will find below.
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RC(Cyclic Redundancy Check) is an error - detecting code using for detect accidental changes to RAW data.
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The algorithm how to calculate CRC - 16(also known as CRC - 16 / IBM) you will find below.
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var crc = {
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var crc = {
    extractCRC: function(message){
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    extractCRC: function (message) {
        crcData = message.slice(message.length-2,message.length);
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        crcData = message.slice(message.length - 2, message.length);
        return crcData[0] * 256 + crcData[1];
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        return crcData[0] * 256 + crcData[1];
    },<br>
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    },
    crcCam: function(message, previous_crc){
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    calculateCRC: function(message, previous_crc) {
        payload = message.slice(2, message.length-2);
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        let crc_poly = 0x8408;
        crc = 0x0000;
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        let idx = 0;
        bitOne = 0x0001;
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        let crc = 0x0000;
        crcpoly = 0x8408;
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        idx = 0;<br>
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        /* the payload length is calculated with removing size of header and CRC (4 + 2 bytes) */
        /*At this point you should start with the init value for CRC calculation. Init value for
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        let payload_length = message.length - 6;  
        * the first packet is zero and for the upcoming packets it is the CRC value of the previous package
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        */
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        /* the payload is separated from the message header and CRC (4 bytes ofset + length)*/
        crc = previous_crc<br>
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        let payload = message.slice(4, 4 + payload_length);
        while (idx < payload.length) {
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            /* Use XOR operation for initial value and payload */
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        /* Init value for the first message is zero and for the upcoming messages it is the CRC value of the previous message */
            crc ^= payload[idx];
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        crc = previous_crc;
            bitcounter = 0;<br>
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            while (bitcounter < 8) {
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        for (idx = 0; idx < payload_length; idx++) {
                crcFirstBit = crc & bitOne;
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            let bit;
                crc >>= 1;<br>
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                if (crcFirstBit) {
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            /* Use XOR operation for initial value and payload */
                    crc ^= crcpoly;
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            crc ^= payload[idx];
                }
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            }
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            for (bit = 0; bit < 8; bit++) {
            idx = idx + 1;
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                let carry_bit = crc & 0x01;
        }
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                crc >>= 0x01;
        return crc;
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                if (carry_bit != 0) {
    }
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                    crc ^= crc_poly;
};
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                }
exports.crc = crc;
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            }
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        }
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        return crc;
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    }
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};
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exports.crc = crc;
    
==File transfer visual flow==
 
==File transfer visual flow==

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