Unveiling USBHUB3+ Enumeration Speed: How to Determine Your Connected Devices' Speed

2023 October 10

Learn how to determine the enumeration speed of devices connected to USBHUB3+ and whether they're operating at high or super speeds.

Each port on USBHub3+ can operate in High Speed or Super Speed modes. There are three ways to view the speed of a connected port

  1. Front panel LED

  2. HubTool virtual LED

  3. Brainstem API

Connecting a USB 2.0 device to port 0, you should see a yellow LED on the hub front panel, and a corresponding yellow box in HubTool indicating a high-speed connection.


Port speed on a USBHUB3+ can also be queried using Python. We'll be working in an interactive Python console to be able to work line-by-line.  

If you haven’t already, install the Brainstem package (See the Quickstart Guide for more detail)

>>> import brainstem

Create an instance of the USBHub3p called "hub"

>>> hub = brainstem.stem.USBHub3p()

Discover and connect to the hub

>>> hub.discoverAndConnect(brainstem.link.Spec.USB) 0

A return value of 0 means no error.  

>>> hub.usb.getDownstreamDataSpeed(0).value

High Speed connection:

Value Hub Downstream Speed Descriptions
0 No device enumerated
1 High-Speed device enumerated
2 SuperSpeed device enumerated


The speed description refers to which data lines are active.  An iPhone connected via lightning at up to 480 Mb/s and a USB mouse at up to 1.5 Mb/s would both appear as High-Speed devices on the hub and HubTool LEDs and return a "1" because they are using the USB 2.0 High-Speed data lines.

What else could you do with USBHub3+?


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