How does a usb hub work?

[GreenAce92]

How do you have a four-port usb hub consolidate to one usb port and the computer knows which usb is talking to it at any given time?
I think of like a keyboard (multiplexer?) but a friend says "Serial Communications", I accept to be wrong but why all the articles don't seem to actually explain how... just mentions things like speed, power limitations...

 

[FvM]

For a basic idea, I suggest the page "USB is a bus" from USB made simple https://www.usbmadesimple.co.uk/ums_3.htm

The full answer is in the USB Data Flow chapter of the USB spec.

 

[GreenAce92]

I'm wondering if this question is not as simple as a multiplexer or serial communications, I keep seeing packets,interrupt,downstream... it was an argument but I will read the link again. Thanks.

I wasn't sure if the green squares were from you but that wouldn't make sense unless you hosted the file yourself/had the capacity to edit.

Anyway thanks

random thought:

Why is there a Post New Thread button on the bottom left? Why isn't that at the top-right?

- - - Updated - - -

I'm wondering if this question is not as simple as a multiplexer or serial communications, I keep seeing packets,interrupt,downstream... it was an argument but I will read the link again. Thanks.

I wasn't sure if the green squares were from you but that wouldn't make sense unless you hosted the file yourself/had the capacity to edit.

Anyway thanks

random thought:

Why is there a Post New Thread button on the bottom left? Why isn't that at the top-right?

 

[FvM]

I'm wondering if this question is not as simple as a multiplexer or serial communications, I keep seeing packets,interrupt,downstream...

Definitely not that simple. To use an ethernet analogy, an USB hub is more like a switch, it's storing and forwarding packets, possibly translating the data rate.