USBDevice: controlTransferIn() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web Workers.

The controlTransferIn() method of the USBDevice interface returns a Promise that resolves with a USBInTransferResult when a command or status request has been transmitted to (received by) the USB device.

Syntax

js
controlTransferIn(setup, length)

Parameters

setup

An object that sets options for. The available options are:

requestType

Must be one of three values specifying whether the transfer is "standard" (common to all USB devices) "class" (common to an industry-standard class of devices) or "vendor".

recipient

Specifies the target of the transfer on the device, one of "device", "interface", "endpoint", or "other".

request

A vendor-specific command.

value

Vendor-specific request parameters.

index

The interface number of the recipient.

length

The maximum number of bytes to read from the device. The actual data is in the USBInTransferResult in the resolved Promise.

Return value

promise that resolves with a USBInTransferResult.

Specifications

Specification
WebUSB API
# dom-usbdevice-controltransferin

Browser compatibility