<!--
{
  "availability" : [
    "DriverKit: 19.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "USBDriverKit",
  "identifier" : "/documentation/USBDriverKit/tIOUSBEndpointDirection",
  "metadataVersion" : "0.1.0",
  "role" : "Enumeration",
  "symbol" : {
    "kind" : "Enumeration",
    "modules" : [
      "USBDriverKit"
    ],
    "preciseIdentifier" : "c:@E@tIOUSBEndpointDirection"
  },
  "title" : "tIOUSBEndpointDirection"
}
-->

# tIOUSBEndpointDirection

The direction of data transfers on an endpoint.

```
enum tIOUSBEndpointDirection : unsigned int;
```

## Topics

### Getting the Endpoint Direction

[`kIOUSBEndpointDirectionOut`](/documentation/USBDriverKit/tIOUSBEndpointDirection/kIOUSBEndpointDirectionOut)

Data flows from the driver out to the device.

[`kIOUSBEndpointDirectionIn`](/documentation/USBDriverKit/tIOUSBEndpointDirection/kIOUSBEndpointDirectionIn)

Data flows from the device into the driver.

[`kIOUSBEndpointDirectionUnknown`](/documentation/USBDriverKit/tIOUSBEndpointDirection/kIOUSBEndpointDirectionUnknown)

The transfer direction is unknown.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)