Project on Maximum USB connections permitted at a given time

Asked By Christian M Harlow 25 points N/A Posted on - 10/20/2014

I have been Given a project as my Research Work, and was curious to know the maximum possible number of simultaneous USB connected devices at the given time. Could it affect the quality of transfer and data transfer rate at given instant? Will it make my Laptop hang up frequently ?

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Answered By Sharath Reddy 590495 points N/A #183983

Project on Maximum USB connections permitted at a given time

The maximum number of USB devices that you can connect to a single host controller is 127. This includes both hub devices and USB devices. But in actual use or in actual application, you will run out of bandwidth long before you connect all 127 devices. Out of the 127 USB devices, 22 will not appear as disk devices.

So, to get the actual manageable USB devices that can be connected, you will only have 105 devices. The 127 USB devices is a hard limit of the USB protocol because the ADDR address field is set to 7 bit long. That’s why when you are talking about software, there is no way you can increase this.

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• Posted on - 11/07/2014
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