> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/integrations/third-party-readers/wiegand/t-series-wiegand-troubleshooting.md).

# Wiegand troubleshootimg

Diagnose Wiegand card-format errors, invalid data, inconsistent reads, and unresponsive doors.

#### What are the main Wiegand fault symptoms?

The four main Wiegand symptom categories are:

1. Getting an "Unrecognised card format read at door XXXX" from a door
2. All 1's or 0's in the Details tab after getting "Unrecognised card format read at door XXXX"
3. Getting inconsistent data from a Wiegand-controlled door
4. Getting no response from a Wiegand-controlled door

***

#### What causes each symptom, and how do you resolve it?

### 1. "Unrecognised card format read at door XXXX"

This message means you **are** getting communication from the Wiegand device, which is progress. The next step is to create a **UCF (Universal Card Format)** for the card data being processed.

Creating a UCF is not always straightforward. Contact Gallagher Technical Support to assist. For a card reader, Technical Support will usually ask for the following:

* The contents from the Details tab for **at least three reads from consecutive cards**
* The **card numbers** of the cards being presented
* The **Facility Code** of the cards being presented

From this information, Technical Support will provide a UCF to enter into the controller connected to the Wiegand device.

***

### 2. All 1's or 0's in the Details tab

* **All 1's:** The D0 wire is not connected or has a poor connection.
* **All 0's:** The D1 wire is not connected or has a poor connection.

Check wiring and connections for the affected data line.

***

### 3. Inconsistent data from a Wiegand-controlled door

Usually caused by one of two things:

1. A poor ground connection between the Wiegand device and the Gallagher device.
2. The Wiegand D0 and D1 lines need pull-up or pull-down resistors added.

**Diagnostic steps:**

1. Check the ground connection between the Wiegand device and the Gallagher device. Ensure it is a solid, reliable connection.
2. If the ground is good, add pull-up or pull-down resistors to the D0 and D1 lines. Contact Gallagher Technical Support for guidance on resistor values.

***

### 4. No response from a Wiegand-controlled door

Assuming the Wiegand device is working correctly, there are only two possible causes:

1. **No alarm zone** assigned in the door configuration.
2. **No ground** between the Wiegand device and the Gallagher device.

**Diagnostic steps:**

1. Verify that an alarm zone has been assigned to the door in Command Centre. (A door must have an alarm zone assigned to generate events.)
2. If the alarm zone is correctly configured, check the ground connection between the Wiegand device and the Gallagher device.

> ⚠️ **No ground = no Wiegand communication.** Even if power is supplied externally, the ground reference between devices must be present.

***

🔗 **Related**

* [T Series - Wiegand Troubleshooting Introduction](/knowledge-hub/products/integrations/third-party-readers/wiegand/t-series-wiegand-troubleshooting-intro.md). The protocol, connections, and pull-up resistors.


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