usability – has USB-A always been designed to be reversible?

It is probably the opposite. people who have connection problems with the old connector get the idea of ‚Äč‚Äčreversible connectors.

1 – There is not enough space.

Although I have not found an official specification regarding the thickness of the white plastic part, here is a series of vendor diagrams that show that this is exactly or very very close to the connector axis.

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cropped from this image via jj-conn.diytrade.com

The entire connector has a thickness of 4.5 mm, while the white portion ends at 2.3 mm. The absolute center would be 2.25, so there is a gap of 0.05 mm, but it is to drag it and the variance of materials. 0.05 or even 0.1 mm (one or two sheets of printer paper) is not thick enough for a contact board. As a comparison, the already fragile contact table is 0.7 mm.

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cropped from omron data sheet

Although it does not have as many measurements, it shows the center line and you can see that the connector touches just about everything; only one pixel or two difference.

Basically, the two plastic parts (male and female) of the USB are the same size and are placed in the middle of the metal case. I guess / guess it's either for simplicity of production (both sides can use the same PCB), or to guarantee that both are about as strong / durable. Apart from a production margin, there is no space left.


2 – They did not know it would be a problem.

Older computer connectors tended to use slightly trapezoidal connectors. These would be recognizable by the outer shape of the connector. PS2 connectors were also very visible. As are the network cables. And none of these should be exchanged very often.

Things like headphone jacks have been designed to be used a lot, but they are extremely omnidirectional.

USB-A is somewhere in between. he looks reversible, but that's not it. Yet, it is used a lot. This is the first (common) cable that showed reversibility could be a problem.

Of course, the setback is 20/20 and it should have been tested, but at least we now have USB-C in response to this first world problem.


3 – You could make it reversible, but it would not look like USB-A at all.

USB-A currently has an individual connection, each party occupying 50% of the space. To make it reversible, you will need a one-to-one connection. You can have two tips for the woman and a man at the center or two tips for men and a center.

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red is a man, blue is a woman.

And the 2 men with 1 female version is essentially USB-C.


4 – It would be weaker.

The smaller an element, the more fragile it is. USB-A currently has an individual connection, each party occupying 50% of the space. To make it reversible, you would have to clear one or both sides, because you would have a connection one by two. You would have 3×33%, or 1×50% and 2×25%, or something similar.

It would also be more complex because there would be more elements to wire and therefore more things that could break.

And one last thing that could be lost, is that in variant 1M-2F, none of the cards would be connected to the metal shell. With USB-A and USB-C, the male card touches the case, which means that it can not bend. However, in all 3 variants, the female board remains floating and therefore fragile.

Note; Fragility is actually a point of criticism for USB-C, and I am inclined to accept. I think that a configuration more like lightning cables would be more solid, at least for female connectors. And the female connectors tend to be in electronic components (expensive), while the male connectors are connected to cables (less expensive to replace).


5 – How do the reversible?

They take all possible leeway with the specifications.

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According to the omron scheme, the case measures 5.12 mm with a sheet thickness of about 0.2 mm. This leaves 4.72 mm for a very tight connector. The connector is only specified at 4.5 mm, which leaves
0.22 mm. If you also reduce the thickness of the sheet from 0.2 to 0.1 mm, you get an additional 0.2 mm. A total of 4.2 mm. If we add card bending and other places to bend the rules, we can get closer to the 0.7mm thickness of a USB-C connector.

Of course. this has several disadvantages. On the one hand, it is obvious that the whole construction is more fragile. Two, because everything is pushed to the limit, it will be very difficult to set up and there may even be ports in which you literally can not insert it. Thirdly, bending means that you have a very small contact area.

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So overall, this does not seem to be a very resilient connector, but a pretty smart hacking.

Connect an iPad Pro to an old Macbook Pro using a generic USB-C to USB-A cable

The old Macbook Pro I'm using does not have USB-C ports. The cable that comes with the iPad Pro that I use comes with a USB-C to USB-C cable. I've tried using a USB-C to USB-A cable from a Huawei phone to connect the iPad and the Macbook, but there was no connection.

Does this mean that I will have to get a very specific USB-C to USB-A cable, such as a Belkin USB-A to C-USB cable (USB 3.1) (see https: // support.apple.com/en-us/HT209186#computer)?

usb 3 – Using the USB-C Port Replicator Hub with a Laptop and a USB-A Desktop Computer

So I just bought a Lenovo USB-C (Port Replicator) hub that I want to use with my laptop and my desktop. However, none of my devices have USB-C ports and I can only use USB 2.0 or USB 3.0 ports with an adapter.

The hub in question is: https://www.amazon.co.uk/gp/product/B07FQD4KMV

The adapter in question is: https://www.amazon.co.uk/gp/product/B01J16IOIS

It turns out that the initially planned configuration does not work. I do not know why, but I guess the conversion of USB-C to USB-A makes the hub undetectable for Windows 10.

I was wondering if the hub or the adapter were not working properly, but after testing with other devices, I concluded that the problem was related to the USB ports of the laptop and the office.

Do you have any ideas on how to get around this problem? I think that as a last resort, I may have to buy and install a PCI Express USB-C adapter card on the desktop, but I do not know what to do with a laptop.