Wiegand-26-dat
Wiegand-26 is a widely used RFID access-control data format, not a wireless protocol.
It defines how card data is encoded into 26 bits and transmitted from a reader to a controller.
Correct name: Wiegand-26
Common misspelling: Wigan-26
What Does Wiegand-26 Do?
It specifies the bit structure and wiring method used to send an RFID card’s ID from:
- RFID reader → Access controller
It does NOT define:
- RF frequency (125 kHz / 13.56 MHz)
- Card chip type
- Encryption method
Wiegand-26 Bit Structure
Total: 26 bits
| Bit Position | Purpose |
|---|---|
| Bit 1 | Even parity (first 12 bits) |
| Bits 2–9 | Facility Code (8 bits) |
| Bits 10–25 | Card Number (16 bits) |
| Bit 26 | Odd parity (last 12 bits) |
Capacity
- Facility codes: 0–255
- Card numbers: 0–65,535
Electrical Interface
-
Two data lines:
-
DATA0→ pulse = logic 0 -
DATA1→ pulse = logic 1
-
-
Plus:
- GND
- Power (usually 5–12 V)
No clock line — timing is pulse-based.
Typical Use Cases
- Door access control
- Time & attendance systems
- Parking gates
- Elevators
Very common in:
- 125 kHz proximity cards
- Low-cost access systems
Advantages
- Simple
- Very widely supported
- Easy to integrate with controllers
Limitations ❌
- No encryption
- Card ID is transmitted in plain form
- Vulnerable to cloning
- Short cable length (typically < 150 m)
Comparison with Other Formats
| Format | Bits | Security | Notes |
|---|---|---|---|
| Wiegand-26 | 26 | Low | Most common legacy |
| Wiegand-34 | 34 | Low | Larger card ID |
| Wiegand-37 | 37 | Low | Used by HID |
| OSDP | Packet-based | High | Encrypted, RS-485 |
Important Note
Wiegand-26 is a data format, not RFID itself.
You can have:
- 125 kHz + Wiegand-26
- 13.56 MHz + Wiegand-26
They are independent layers.