User's Manual

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HID Corporation, 9292 Jeronimo Road, Irvine, CA 92618-1905, USA •Tel: [phone], Fax: [phone]
http://www.hidcorp.com MaxiProx Reader Installation Manual 5375-900 REV 06
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Chapter 4 Application Notes
4.1
4.1 4.1
4.1 Wiegand Interface Description
Wiegand Interface DescriptionWiegand Interface Description
Wiegand Interface Description
4.1.1 Wiegand Message Format
In the Wiegand format, the ID card is programmed with a specific bit pattern and the Reader acquires the
data, checks the customer code and generally sends out the same bit pattern as previously programmed on
the card. Consult factory for variations to this method. A 26 bit Wiegand format will be used in the examples
below.
The 26 bits of transmission from the Reader to the panel consists of two parity bits and 24 code bits. The
bits are transmitted in the order described. The first bit transmitted is the first parity bit, P1; it is even parity
calculated over the first 12 code bits. The last bit transmitted is the second parity bit, P2; it is odd parity
calculated over the last 12 code bits:
Code Format
11111111112222222
12345678901234567890123456
P1CCCCCCCCCCCCCCCCCCCCCCCCP2
Parity Format
11111111112222222
12345678901234567890123456
P1EEEEEEEEEEEE
OOOOOOOOOOOOP2
 P1: First, or even parity bit

C: Code bits

P2: Second, or odd parity bit

E: Bits for calculation of even parity

O: Bits for calculation of odd parity
Data format within the 24 code bits which includes the portioning of the bit, the designation of the Most
Significant Bit (MSB)
or the Least Significant Bit (LSB) shall be subject to definition by the panel and
Reader manufacturers and may remain proprietary.
4.1.2
Output Specification
The specifications of voltage, current, power and timing are from the perspective of the Reader. A common
signal ground is defined as a voltage reference that is common to both the Reader and the control panel. The
voltages for the data outputs are referenced from the power supply ground located at the Reader. The
voltage measured for the power to the Reader is referenced from the power supply-return connection location
at the Reader, not at the source of the power.