PA22
User Manual
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Appendix1 Wiegand Introduction
Wiegand26 Protocol is a standard protocol on access control developed by the Access Control Standard
Subcommittee affiliated with the Security Industry Association (SIA). It is a protocol used for contactless IC
card reader port and output.
The protocol defines the port between the card reader and controller which are widely used in access
control, security and other related industries. This has standardized the work of card reader designers and
controller manufacturers. The access control devices produced by our company also apply this protocol.
Digital Signal:
Figure 1 shows the sequence diagram of the card reader sending a digital signal in bits to the access
controller. The Wiegand in this diagram follows the SIA access control standard protocol, which targets at
26-bit Wiegand card reader (with a pulse time within 20us to 100us and pulse hopping time within 200us
and 20ms). Data1 and Data0 signals are high level (greater than Vol) until the card reader is ready to send
a data stream. The card reader sends out an asynchronous low-level pulse (less than vol), transmitting data
stream via Data1 or Data0 wire to access control box (as the sawtooth wave in figure 1). Data1 and Data0
pulses do not overlap or synchronize. Figure 1 shows the maximum and minimum pulse width (successive
pulses) and pulse hopping time (the time between two pulses) allowed by the F series fingerprint access
control terminals.
Sign
Definition
Card Reader Typical Value
Tpw
Pulse Width
100 µs
Tpi
Pulse Interval
1 ms
Table1: Pulse Time
Figure1: Sequence Diagram
