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POHow could I guess a checksum algorithm?
 

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  1. POHow could I guess a checksum algorithm?
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    <p>Does anybody know how to figure out the CRC algorithm if a given code + CRC string is given? </p> <p>I have got several strings consisting of code + matching CRCs but don´t know how to calculate the CRC in question so that I could produce more code strings. Here are some samples (16bit code + 4bit CRC):</p> <pre> 0010101000011101 + 0000 0010101000011111 + 0001 1000110011101101 + 0001 0000000000000100 + 0010 0011100011001110 + 0011 1000110011101110 + 0100 0001011110101100 + 0100 0010101000011110 + 0101 0011100011001101 + 0110 0001011110101111 + 0111 0011100011001100 + 1001 0011100011001111 + 1010 0001011110101101 + 1011 0000000000001000 + 1011 0000111100001101 + 1100 0000000000001100 + 1100 1111111111111111 + 1101 1000110011101111 + 1101 1000110011101100 + 1110 0001011110101110 + 1110 1111111100001101 + 1110 0010101000011100 + 1111 </pre> <p>These codes come from a RF (433MHz) sender like the X10 products.</p> <p>I am not sure if this is a CRC or what it is, but at least it calculated somehow out of those code strings.</p> <p>Can anyone help?</p> <p><strong>Updates:</strong></p> <p>RE: finding the specifications I also think would be the best solution but since this is no option I need to brute force the checksum calculation somehow.</p> <p>This is the problem, I don´t have the specifications and I can´t get them anywhere. I have tried several different checksum calculation methods without result, isn´t there a way to compare the input strings finding out what they have in common and this way getting the algorithm</p>
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    1. CORelated: http://stackoverflow.com/questions/283556/tricky-crc-algorithm
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    2. COExplain what an RF sender and the X10 stuff is. Maybe http://www.x10.com/minisites/videosender/rf_systems_pro_3250_wireless_video_sender.html is related. In which case, you - Tom - should have explained to us what you are after. We should not have to guess what you are after!
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      1. USJonathan Leffler
    3. CORF outlets(EMW100) are from www.everflourish.com.cn,rebranded to Cotech,selled by www.clasohlson.fi, transmitter - http://www.clasohlson.se/Archive/Images/Products/Hi/361183A_X_2007-06-27_161950_278.jpg, remote - http://www.clasohlson.se/Archive/Images/Products/Hi/361183C_X_2007-06-27_162028_434.jpg
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