h10301

Understanding 26-Bit Wiegand Format: Proximity Cards & Access Control

Understanding 26-Bit Wiegand Format: Proximity Cards & Access Control - TagtixRFID

 

 

Understanding the 26-Bit Wiegand Format for Access Control Systems

The 26-bit Wiegand format is one of the most widely used standards for access control systems, particularly in legacy installations.

It’s an open format, meaning that any organization can implement and use it, and multiple manufacturers produce cards compatible with this system. 

What Is the Standard 26-Bit Wiegand Format?

At its core, the 26-bit Wiegand format is a method of encoding binary data to identify individuals via access cards, key fobs, or other devices. 

The term “bit” refers to the smallest data unit, either a 0 or a 1, which makes up the digital code stored on these cards. The format follows a structured design where the data is split into three main components:

  • Parity Bits: The first and last bits in the 26-bit sequence are parity bits. These are used for error checking to ensure the data is transmitted correctly, but they do not contribute to the unique identification number on the card.

  • Facility Code: The second through ninth bits (8 bits in total) represent the facility code or site code. This code identifies the specific location or organization that issued the card. The facility code can range from 0 to 255, allowing for 256 unique facility codes.

  • Card Number: Bits ten through twenty-five (16 bits) store the ID number assigned to the individual cardholder. This number can range from 0 to 65,535, meaning there can be over 65,000 unique cardholders per facility.

When combined, the 26-bit format provides 16,711,425 unique card combinations (256 facility codes multiplied by 65,536 card numbers), making it a popular choice for standard access control systems.

How Does the 26 Bit Wiegand Format Work?

The Wiegand format is named after John R. Wiegand, who discovered the principle behind it in the 1970s. He found that certain metal wires change polarity when exposed to a magnetic field, which could be used to transmit binary data. This discovery laid the foundation for modern access control systems.

 

wiegand protocol explained

Access cards using the 26-bit Wiegand format have a simple structure consisting of three wires inside: data0, data1, and ground. These wires transmit binary signals (0s and 1s) to the reader. When a card is scanned, the reader detects the signal changes from the data0 and data1 wires, converting the signals into the corresponding binary sequence.

  • When the data0 wire sends a signal, it is read as a 0.
  • When the data1 wire sends a signal, it is interpreted as a 1.

Once the reader receives this data, it decodes the information, checks the parity bits for accuracy, and then compares the facility code and card number to the stored database. Access is granted if the facility code and card number match the authorized entries in the system. If not, access is denied.

Why Is the Wiegand 26-Bit Format Still in Use in Access Control?

Despite being a relatively older technology, the 26-bit Wiegand format remains in use for several reasons:

  • Simplicity: It’s easy to implement and integrate with many existing access control systems. Most access control systems automatically support the 26-bit format, making it convenient for organizations to adopt without requiring complex configurations.

  • Availability: The open nature of the 26-bit Wiegand format means that it’s widely available. Many manufacturers produce prox cards in this format, which has led to its continued use in older buildings and facilities that prioritize cost-efficiency over cutting-edge security.

However, there are security concerns. Since the 26-bit format is not encrypted and duplicates can be created, it’s not suitable for high-security environments.

As technology has evolved, more secure formats like OSDP (Open Supervised Device Protocol) have been developed to offer encryption and enhanced security features.

How to Identify if Your System Uses the 26-Bit Wiegand Format

To determine whether your access control system or card uses the 26-bit Wiegand format:

Check the Documentation:

The easiest way is to check the system or card documentation, which often includes details on the card format, facility code, and card range.

Look for the H10301 Identifier

The H10301 format is a common name for the 26-bit Wiegand format. If this is listed on your card packaging or system, it confirms that the format is in use.

Consult Your Access Control Provider

If you’re unsure about the format, contact your access control provider. They can usually confirm the card format based on the equipment and system configuration.

Use a Card Reader

You can also scan the card with a card reader to retrieve the facility code and card number. Many readers will display the card’s bit length, and if the card contains 26 bits, it’s likely using the Wiegand H10301 format.

FAQ

What is the 26-bit Wiegand format used for?

The 26-bit Wiegand format is commonly used in access control systems to encode and transmit data between Wiegand cards and card readers. It’s widely used in HID systems for secure access to buildings and facilities.

How does the 26-bit Wiegand interface work?

The Wiegand interface transmits binary data from a card to the reader through data low and data high wires. This interface is used in the vast majority of access control systems, including HID ProxPoint Plus and ProxPro.

What is the H10301 Wiegand format?

The H10301 Wiegand format is the 26-bit Wiegand format, commonly used for encoding data on HID cards. It includes 8 bits for the facility code and 16 bits for the card number, making it widely compatible with most access control systems.

Why is the 26-bit Wiegand format the most commonly used in access control?

The 26-bit Wiegand format is popular because it’s an open, simple, and widely supported standard. It’s used by the majority of access control systems and compatible with many 125khz prox card readers.

How does the Wiegand protocol differ from other access control methods?

The Wiegand protocol uses a specific wiring standard to transmit binary data via data low and data high wires. Other methods, like NFC or encrypted protocols, may use wireless transmission or additional security features. 

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