why isn't it ok? why????

Huh, I'm not sure they are comparable.

Didn't USB A and USB B use a master-slave relationship in which the male would (generally) always be the slave, whereas USB C uses agreement and discussion to decide the master and slave roles regardless of connector gender.

Please do correct me if I'm wrong. Also, do we say "agent" now instead of "slave", or what is the new term?

USB-A male to USB-A male is not in any USB standard (not entirely true, but compliant cables are very rare and don’t connect voltage), and if you plug it into a device it’s not meant for, the behavior is entirely unspecified. It will probably do nothing. But it might fry your USB controller that is not expecting to receive voltage.

USB-C to USB-C is in the spec, and if you plug in two host devices, they won’t hurt each other. You can actually charge a host device over USB-C, unlike USB-A.

That’s why it isn’t ok. It’s not the same thing, it’s not in the standard, and it can even be dangerous (to the device).

A to B made more sense in a world where devices cannot serve as both roles via negotiation. My android phone when I got it utilized a data transfer method of plugging my iPhone charge port into my Android charge port, then the Android initiated the connection as a host device.

The true crime is not that the cable is bidirectional, the true crime is that there is little to no proper distinction and error checking between USB, Thunderbolt, and DisplayPort modes and are simply carried on the same connector. I have no issues with the port supporting tunneled connections - that is in fact how docking stations work - just the minimal labeling we get in modern devices.

I'd be fine with a type-A to type-A cable if both devices had a reasonable chance at operating as both the initiator and target - but that type of behavior starts with USB-OTG and continues in type-C.

The USB spec requires one master and one slave device, which is usually decided by which type of connector each side has. USB OTG can bypass that restriction, but I've only ever seen it done with micro USB or type C.

USB-A requires three attempts to connect, C only one.

I guess the usb spec makes you sick then.

With the the first one you can fry your gear, while stuff that takes the second one does auto negotiation.

I realy don't want a cable i plug both ends in wrong and have to turn them a couple of times

Well, if you have asymmetric cables, there's always one clearly-defined host and the other one is the slave.

it works like sex: with usb-c, both devices more or less kinda have ti "negotiate" who's dom and who's sub. that takes extra negotiation effort and makes the protocol more complicated. and therefore more expensive imo.

In the long, long ago, we used to use USB-A to A cables to transfer customers' Mac OS X user profiles when they would buy a new Mac. Also worked with Target Disk Mode, way back when.

I've never seen a USB-A to A cable in the wild, except recently, where I finally unpacked my SATA/IDE USB adapter from Ugreen.

It is a fact that USB-C is superior. Right off the bat, no more guessing if the end of the cable is facing correctly to be inserted into a port. My patience would quickly wear thin when I'd have to flip it around 3-4 times to finally insert it.

What's a common thing that would require the use of USB A on both ends?

"they are the same picture" -my wife

Who are these people?

What if I put a C-to-A Adapter on both ends? Is that okay?

actually they would be correct :

USB began as a protocol where one side (USB-A) takes the leading role and the other (USB-B) the following role . this was mandated by hardware with differently shaped plugs and ports . this made sense for the time as USB was ment to connect computers to peripherals .

however some devices don't fit this binary that well : one might want to connect their phone to their computer to pull data off it , but they also might want to connect a keyboard to it , with the small form factor not allowing for both a USB-A and USB-B port. the solution was USB On-The-Go : USB Mini-A/B/AB and USB Micro-A/B/AB connectors have an additional pin which allows both modes of operations

with USB-C , aside from adding more pins and making the connector rotationally symmetric , a very similar yet differently named feature was included , since USB-C - USB-C connections were planed for

so yeah USB-A to USB-A connections are explicitly not allowed , for a similar reason as you only see CEE 7 (fine , or the objectively worse NEMA) plugs on both ends of a cable only in joke made cables . USB-C has additional hardware to support both sides using USB-C which USB-A , neither in the original or 3.0 revision , has .

It's about the winding and not about the USB version, right?

I have an external 3.5“ HDD enclosure that has a USB-A port to connect the usb cable to. I have no idea who thought that was a good idea. The difference in price to a B connector can’t be that significant…

I'm not sure what the point is here. C is symmetrical and has absolutely no downsides, so yes, it's objectively better.

I am a stupid end user. But I've never found an instance where I needed male to male cords.

My WH1080 weather station has a USB-A connector on the device side, I assume for the convenience of the slimmer profile.

That's the only natural occurrence of that cable I've ever seen.

The other one was a custom board printed in 2001 at the electronics class, where I was some kind of precursor by powering it with a USB cable rather than a bulky lab power supply. As I did salvage the connector it was a A-A abomination but they had that cable at the supermarket for some reason ¯_(ツ)_/¯

I actually found an A to A cable in my Big Box of Cables I Might Need One Day™ when trying to flash my Gotek floppy emulator with FlashFloppy firmware.

I read the Wikipedia a little and apparently A to A cables can damage your devices, and the ones that do exist are for specific purposes and should only be used in those specific scenarios, and often they are more than just cables and have some computational stuff inside them

We peaked at USB mini B.

I actually have several USB-A to USB-A cables.

I actually have a double sided male A cable. I was shocked when I got it but I have this laptop cooler that has two A ports on it, presumably to allow a pass through but I'm always nervous that I'll plug it in and fry something.

If I remember correctly you can't do data copy with A to A. I maybe wrong but I'm to lazy to look up.

I actually thought this was about rolling up cables: circling on the top and over-under at the bottom

I bought a charging pad once that had a USB c connector but none of the 40 USB power adapters I have have one so I returned it. IDK wtf they were thinking. Just make the wall end an A connector like everyone else has been doing for a decade.