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Hi Guys,
I have two cards, that are for Alarm lock, HID compatible 36 bit. Trying to figure out the parity calculation. Bit structure looking like the following:
Card ID = 1127069 (26 bits), FC = 19 (8 bits), 2 party bits, one upper and one lower
P IIIIIIIIIIIIIIIIIIIIIIII FFFFFFFF P
0 00000100010011001010011101 00010011 1
Card ID = 546084, FC 19
1 00000010000101010100100100 00010011 0
Does not make much sense to me...usually you split the Weigand data down the middle and compute either an odd or even parity on the upper and lower end. I can't see to do that consistently with these two cards and I wonder if anyone has an idea.
Thanks in advance,
HKPLUS
Last edited by hkplus (2015-11-04 04:40:09)
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Thanks marshmellow. I saw that already and unfortunately it does not provide the parity calculation info...
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it does - in the image file
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Maybe it does actually and I don't understand it as of yet...sinking in...
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Do you understand what they are talking about...offset and 35 bits? Looks like 1 parity is the opposite of the other...all bits are computed for both even and odd parities?
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it works doesn't it?
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Only with these two samples, the only two that I have...
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the image file is from the security company itself. i see no reason to doubt it.
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to check yourself in your understanding of the image file they have an image file for standard 26 bit to compare to.
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Don't doubt it, just didn't understand it. The offset stuff was throwing me off, but that just means that you just look at the data portion to compute the lower even parity.
Do you have any knowledge on the Keri K card format? Looks like an Indala type and really scrambled...?
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Also looking at the Keyscan 36 bit format for kicks...got it figured out but I think my parity calculation is wrong...
Last edited by hkplus (2015-11-04 05:05:01)
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as for keri, i think i only had the 26W format started. i believe it is an old format though. but it is very much like indala.
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hmmm what keyscan? i don't see one on their site.. what am i missing now?
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Thanks for the help. Let me see if I can get back to you, in order to fill in unknowns in the Keri format.
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