(pure curiosity) The first time I've seen a USB 3.0 B-type connection in the wild

mikeymikec · Jan 28, 2025

This kind of connection (left):

Iiyama monitors with USB ports typically (at least in my experience) use the USB 2.0 B connection (typical printer connection), but for example the XUB2463HS model has a USB 3.2 hub built-in. The specs say that the 2.0 hub on other Iiyama monitors can handle up to 500mA but the 3.2 hub can handle 900mA.

I thought that part of the point of the larger 3.0 B connection was to supply extra power (this is incorrect since a USB 3.0 port can only supply 900mA) and therefore the reason why I've rarely seen it in the wild is because usually if a device requires more power then it will have a mains connector. I wonder why a USB 3.0 B connector is shaped so differently from a 2.0 B connector then. Any ideas?

Paperdoc · Jan 28, 2025

You misunderstand the Type B connector. Specifically it does NOT contain power lines - it has ONLY the DATA lines. That is why it was so widely used to connect to a printer. The printer MUST have access to much more than the 5 VDC 0.5 A available from a standard USB2 connection, and more even than USB 3.2's 0.9 A. Likewise for a monitor, but when the monitor ALSO contains a USB 3.2 HUB (which should be designed to provide up to 0.9 A max current per output port), obviously that unit MUST have more than the power available from a single host computer USB 3.2 port. So your monitor has a Type B USB 3.2 input cable (carrying 5 data lines) from the host and its own internal USB 3.2 power supply module to provide the power output required on its Hub ports.

tcsenter · Monday at 5:04 AM

Huh? Type B has the sames # pin/wires as Type A, carrying +VCC and -GND pins for power. Same with USB 3.x. There are three reasons for introducing the USB Type "B" connector:

-prevent host to host connection (between two PCs)
-mechanically more "beefy" and secure connection
-'signal' to the user they were dealing with a peripheral or device that (likely) could not run from "bus power" over the USB cable and would require separate power

There may have been some potential benefit from the slightly greater spacing/arrangement of the pins on USB B compared to the 'linear' (side by side) arrangement of the USB Type A, that could conceviably reduce crosstalk and interference using an insulator or shielded material in the center of them?

mikeymikec · Monday at 6:44 AM

I'll make my question more concise:

Does anyone know why there is a physical difference between the USB 2.0 B-type connector and USB 3.0 B-type connector?

tcsenter · Monday at 7:14 AM

mikeymikec said:
I'll make my question more concise:

Does anyone know why there is a physical difference between the USB 2.0 B-type connector and USB 3.0 B-type connector?

Already answered. And here...

What Is The Mystery Around USB Type-B?

Of what necessity did the USB Type-B plug originate from? Why is it still a thing, and why does it seem like printers and Type-B are in cahoots?

www.usbmemorydirect.com

Edit: Oh sorry. I misread your question. There is a difference between all the USB 2.0 and 3.0 connectors, to accommodate more pins for 3.0. Type A made them internal to the connector.

mikeymikec · Monday at 7:19 AM

tcsenter said:
Already answered. And here...

What Is The Mystery Around USB Type-B?

Of what necessity did the USB Type-B plug originate from? Why is it still a thing, and why does it seem like printers and Type-B are in cahoots?

www.usbmemorydirect.com

Since that doesn't answer the question (it doesn't even acknowledge the difference between a 2.0 B and 3.0 B connector), I'm going to guess the answer:

2.0 B has four connections, 3.0 B has nine. It wasn't possible for whatever reason to fit the 5 additional connections while maintaining backwards compatibility, so the awkward stump on the end of the 3.0 B connector came into being.

I'm sceptical about this explanation because surely if it was possible to make a backwards compatible A type connector and fit in the additional connections there, then logically it ought to be possible to do the same with the B connector. <shrugs>

tcsenter · Monday at 7:21 AM

You got in before my edit!

mikeymikec · Monday at 7:26 AM

I was about to do an edit myself I was going to add to my guess that the total length of the 2.0 B connector (ie. measure the shall we say 'circumference' of the connector) is less than the total length of the A connector so it isn't possible to do everything in that space that can be done with the larger 3.0 B connector.

Paperdoc · Monday at 2:23 PM

tcsenter, I was wrong, so thanks for the proper info. It appears you have OP up to speed now, and the question has been answered clearly.

(pure curiosity) The first time I've seen a USB 3.0 B-type connection in the wild

mikeymikec

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Paperdoc

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tcsenter

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mikeymikec

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tcsenter

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What Is The Mystery Around USB Type-B?

mikeymikec

Lifer

What Is The Mystery Around USB Type-B?

tcsenter

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mikeymikec

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Paperdoc

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