Wiegand technology is one of the most widely used communication protocols in access control systems. In use since the 1970s, it allows data to be transmitted between a reader (card, badge, biometric device) and a controller to determine whether access should be granted or denied.
What does Wiegand mean?
The term “Wiegand” originally comes from a physical effect discovered by German engineer John R. Wiegand. He later gave his name to a wiring interface that became a standard in access control. In practical terms, a Wiegand connection is used to transmit to the controller the data read by a reader whether it’s a tag, a card, or a biometric device.
What is Wiegand 26-bit?
The term “Wiegand 26-bit,” also called “26-bit format,” refers to the most common version of the protocol. It describes how the binary code transmitted when a badge is read is organized. In this format, the sequence begins with a parity bit for error checking, followed by eight bits identifying the company or site. It then contains sixteen bits representing the user’s unique ID code and ends with a trailing parity bit.
Thanks to this structure, the 26-bit format can handle up to 255 installation codes and more than 65,000 unique user IDs. This open format, whose structure is public, is compatible with most access control systems.
Why is Wiegand technology so popular?
In the 1980s, the simplicity and universality of the Wiegand format made it a worldwide reference for access control systems. All equipment could communicate with each other regardless of the manufacturer, which led to massive adoption. Even today, Wiegand technology remains widely used worldwide thanks to its reliability and ease of integration.
Wiegand or RS-485: what’s the difference?
While Wiegand is still present in many installations, an increasingly used alternative is communication via RS-485. Unlike Wiegand, which only works one way (the reader sends data to the controller), RS-485 allows two-way communication, meaning the reader and the controller can exchange information continuously.
RS-485 also offers significant technical advantages: it can transmit data over much longer distances up to several hundred meters and it supports modern, secure protocols. Whereas Wiegand is limited in terms of security, RS-485 can integrate encryption and provide better protection against intrusions and badge duplication.
Wiegand technology is a landmark communication interface in the history of access control. While it dominated the market for decades and is still widely deployed today, its limitations in security and flexibility are driving more and more manufacturers and integrators toward RS-485, a more scalable technology better suited to modern cybersecurity requirements.
