---
title: OPC UA
slug: litmusedge-v1/quickstart-guide/industrial-systems-connection-guide/opc-ua
description: Review the different OPC UA DeviceHub drivers and what they do. 
docTags: 
createdAt: 2022-07-04T20:49:58.000Z
---

:::hint{type="info"}
**NOTE**: If the server is running on Windows, make sure to add the Domain name to the list of local hosts. See the *Hosts File* section in [Configure DNS/NTP Servers](docId\:pz9D0WPBQbUGyh0MH6wyx) for more information.
:::

Here are the major differences for the OPC UA Client drivers:

| **This driver**                                        | **Does this**                                                                                                                                                                                                                              |
| ------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [DeviceHub Agent](docId\:n5DPmd_7X1eCqZxVimhFw)        | Connects to the Litmus Edge DeviceHub Agent, which forwards data from an OPC Classic (Data Access) Server.                                                                                                                                 |
| [OPC UA Client Advanced](docId\:ezRIJipeot9AN_kGPympR) | - Recommended driver to use to connect to an OPC UA Server.
- Has subscribe and polling modes.                                                                                                                                             |
| [OPC UA Client](docId\:CYSORhlYGBTc7-CJiLi0v)          | * Used to subscribe data from OPC UA servers.
* Only sends a message to the broker if the value changes at the server level.
* Subscription interval is defined at the driver level and does not have a polling interval at the tag level. |
| [OPC UA Client Poll](docId\:wz06OtFIN6LdMrxzoMj7i)     | - Polls the OPC UA server at regular user-defined intervals, returning the latest status from all specified nodes.
- As soon as a record is generated, the status is passed to the pipeline to avoid delays in processing.                 |