wiegand-dat
A Wiegand device typically refers to a component in an access control system that uses the Wiegand interface to communicate. This interface is a de facto standard for transmitting data from a card reader (like those for ID badges) to an access control panel.
Key characteristics:
- Data Lines: Uses two data lines, typically DATA0 (D0) and DATA1 (D1).
- Signaling: A pulse on D0 represents a binary '0', and a pulse on D1 represents a binary '1'.
- Format: Data is sent in a specific bit format (e.g., 26-bit Wiegand is common, but many others exist), which includes parity bits, facility codes, and card numbers.
- One-Way Communication: It's generally a one-way communication from the reader to the controller.
- Physical Layer: Originally based on the Wiegand effect in specially prepared wires, though modern readers often emulate this electrical interface.
In short, it's the technology that allows a card reader to send identification data to a control panel to grant or deny access.