Wiegand is a standard interface used as output from contactless card readers. The communication is one-way only: from the reader to the connected device (e.g. WIE232). The physical layer of Wiegand consists of three wires - GND, DATA0 and DATA1. Transmitted data slightly differ depending on the type of Wiegand protocol. The most frequently used protocols are Wiegand 26 and Wiegand 30. The protocol is protected by parity. The advantage of the Wiegand interface is mainly the possibility to connect the reader at a great distance.