Velleman HAA2866 - Manual (Page 33)

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THE 26 BIT WIEGAND DATA OUTPUT FROM THE EM CARDS
The Wiegand protocol for card reading has 1 first parity bit, 24 bits of the Card ID, and 1 stop bit for a
total of 26 bits. The first parity bit is an Even parity bit calculated from the first 12 bits of the code and
the trailing parity bit is an Odd parity bit from the last 12 bits. The data transmitted is in Binary codes
for the Card reading.
Example 1: Wiegand Output of Reading An EM Card
Each EM card or Keyfob is marked with an unique ID in Decimal Digits that is the code read by the
reader. The EM card is also marked with a “3 digit+5 digit” code that does not belong to this system
and can be ignored.
a) The Code Marked on One of The EM Cards :
The ID Code to be read for Wiegand Output The Code does not belong to this system
The Code in Decimal Number : 6 6 1 3 7 7 9
The Code 6 6 1 3 7 7 9 Equivalent to Hex Number : 6 4 E B 1 3
b) Each Hex Number Consists of 4 Bits, Total 26 Bits of Wiegand Data Output from Card Reading:
E 6 4 E B 1 3 O
An Even Parity Bit of 6 4 E = 0 An Odd Parity Bit of B 1 3 = 1
c) The 26 bits Wiegand data sending out in Binary after reading of the card:
0 0 1 1 0 0 1 0 0 1 1 1 0 1 0 1 1 0 0 0 1 0 0 1 1 1
NOTE:
In all the operation configurations of card reading including “Card only”, “Card Secondary User PIN”,
and “Card + Common User PIN”, the card has the priority to be read and all these configurations are
considered of reading a Card. The keypad provides Wiegand Data output for the Card only and the
User PINs attached are NOT taken into account for the Wiegand output.
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