Wiegand26 is an access control standard protocol established by the Access Control Standard Subcommittee affiliated to the Security Industry Association (SIA). It is a non­contact IC card reader interface and output protocol. Wiegand26 defines the interface between the card reader and controller used in the access control, security and other related industrial fields. Wiegand26 helps  standardize  the  work  of  the  card  reader  designers  and  controller manufacturers. The access control products manufactured by our company are also designed by following this protocol.

Digital Signals

The  figure below  is  a  sequence  diagram in  which  the  card  reader  sends digital signals in bit format to the access controller. In this sequence diagram, Wiegand follows the  SIA’s  access control standard  protocol for the  26­bit Wiegand card reader (one pulse time ranges between 20 us and 100 us, and the pulse jump time ranges between 200us and 20ms). Data1 and Data0 are high level (larger than Vol) signals till the card reader prepares to send a data stream. The asynchronous low­level pulse (smaller than Vol) generated by the card reader is sent to the access control panel (The saw­tooth wave as shown in Figure below) through Data1 or Data0. Data1 and Data0 pulses will neither overlap nor be generated synchronously. The table below lists the maximum and minimum pulse width (a consecutive pulse) and pulse jump time (time between pulses) allowed by the F series fingerprint access control device.

Figure: Sequence Diagram 

Table: Pulse Time