This, USB-C is just the connector shape. USB-A is the standard square plug everyone knows, USB-B has several different ends, some more well known than others. The full sized “printer/hub” one, mini-B and micro-B which more people know. USB-A to A cables aren’t common, more akin to an Ethernet crossover cable, so you’re almost always going to see one of the B connectors.
USB-C is just the newest plug design, the actual cable and communication protocols have changed numerous times over the decades. USB-C might have been introduced alongside USB 3.0 and the massive increase in charging and data speeds with the new standard, but they are not exclusive.
The most obvious example is probably the iPhone 15 and 16, both had a USB-C plug, but the devices only supported USB 2.0 protocols.
I believe USB A-to-A cables actually violate the USB spec and should not in fact ever exist. They definitely should not exist as a straight-through cable (although obviously they still do in reality) without any active electronics in the middle. Male A plugs are solely for connecting to a host device, and the entire purpose of the spectrum of B plugs in their various guises is specifically to make the other end of the cable that goes into the endpoint device different. The point is that you are not supposed to be able to directly connect two hosts together like that.
A straight through dumb A-to-A cable would connect the +5v pin from the host device directly to the +5v pin on the device on the other end of the cable. If you did this between two host devices (i.e. two computers) it is certainly possible that Bad Things would happen if the designers of both devices did not account for this type of stupidity. The only way one of these can be valid according to the spec is to omit the power pins entirely.
That said, I have a particular flashlight that came with exactly one of these naughty cables: A straight through male USB A-to-A cable with no smarts in it whatsoever. The flashlight charges via a USB-A port which is exceptionally bizarre, and I suspect the reason it does so is because it can also act as a power bank and the manufacturer was too cheap to include a type C or micro B or whatever port for input and a separate type A port for output. But now I’m stuck having to use the moronic cable it came with (which is also only like 14" long) without much hope of ever finding an alternative or replacement…
Invalid USB-A male to USB-A male cables are also commonly used on low cost KVM switches.
The one I got from Amazon has two of them - one for each computer, then the other end of each cable connects to the switch. The switch has its own micro-USB power supply but it is optional, so the cables must pass power
Speaking of illegal weird cables: I actually have a Y shaped cable, USB Type-A male to USB Type-A female with an extra red USB Type-A male to inject more power if the host can’t power the device otherwise.
I’ve used it once to attach an external HDD to an Android Phone with an OTG male micro-B to female A adapter. It worked but it was kind of stupid :-D
Male to female A-to-A cables are pretty common (they’re just basic extensions) and totally legal under the spec provided they’re limited to a certain length or contain a powered repeater. It’s just the rare male-to-male (which my keyboard stupidly uses) and even rarer female-to-female that aren’t legal. There’s also the exception of USB-on-the-go cables with a micro-B end and a female A end for devices like smartphones that are capable of being host or connecting to a host, back before they switched to USB-C.
Yeah I remember back before CD-R was widespread, having only 3.5" floppies a Zip 100 drive, trying to look into how to move files from our old family computer to a new one.
I did find some sort of software at Best Buy or Circuit City, someplace like that, which used an A-A cable to directly connect two systems.
Yep. These were a stopgap in the days when normal users could not be expected to have a functional home network of any sort. Those were indeed active devices, and had a lump in the middle of the cable that basically amounted to an integrated USB hub.
This, USB-C is just the connector shape. USB-A is the standard square plug everyone knows, USB-B has several different ends, some more well known than others. The full sized “printer/hub” one, mini-B and micro-B which more people know. USB-A to A cables aren’t common, more akin to an Ethernet crossover cable, so you’re almost always going to see one of the B connectors.
USB-C is just the newest plug design, the actual cable and communication protocols have changed numerous times over the decades. USB-C might have been introduced alongside USB 3.0 and the massive increase in charging and data speeds with the new standard, but they are not exclusive.
The most obvious example is probably the iPhone 15 and 16, both had a USB-C plug, but the devices only supported USB 2.0 protocols.
I believe USB A-to-A cables actually violate the USB spec and should not in fact ever exist. They definitely should not exist as a straight-through cable (although obviously they still do in reality) without any active electronics in the middle. Male A plugs are solely for connecting to a host device, and the entire purpose of the spectrum of B plugs in their various guises is specifically to make the other end of the cable that goes into the endpoint device different. The point is that you are not supposed to be able to directly connect two hosts together like that.
A straight through dumb A-to-A cable would connect the +5v pin from the host device directly to the +5v pin on the device on the other end of the cable. If you did this between two host devices (i.e. two computers) it is certainly possible that Bad Things would happen if the designers of both devices did not account for this type of stupidity. The only way one of these can be valid according to the spec is to omit the power pins entirely.
That said, I have a particular flashlight that came with exactly one of these naughty cables: A straight through male USB A-to-A cable with no smarts in it whatsoever. The flashlight charges via a USB-A port which is exceptionally bizarre, and I suspect the reason it does so is because it can also act as a power bank and the manufacturer was too cheap to include a type C or micro B or whatever port for input and a separate type A port for output. But now I’m stuck having to use the moronic cable it came with (which is also only like 14" long) without much hope of ever finding an alternative or replacement…
Invalid USB-A male to USB-A male cables are also commonly used on low cost KVM switches.
The one I got from Amazon has two of them - one for each computer, then the other end of each cable connects to the switch. The switch has its own micro-USB power supply but it is optional, so the cables must pass power
Extra crispy. I wonder if a replacement cable for one of those will work with my flashlight. It probably will.
Speaking of illegal weird cables: I actually have a Y shaped cable, USB Type-A male to USB Type-A female with an extra red USB Type-A male to inject more power if the host can’t power the device otherwise.
I’ve used it once to attach an external HDD to an Android Phone with an OTG male micro-B to female A adapter. It worked but it was kind of stupid :-D
Those used to be common for stuff like external drives (HDD, DVD…)that needed more power than old USB ports could provide, so they used two
Male to female A-to-A cables are pretty common (they’re just basic extensions) and totally legal under the spec provided they’re limited to a certain length or contain a powered repeater. It’s just the rare male-to-male (which my keyboard stupidly uses) and even rarer female-to-female that aren’t legal. There’s also the exception of USB-on-the-go cables with a micro-B end and a female A end for devices like smartphones that are capable of being host or connecting to a host, back before they switched to USB-C.
Yeah I remember back before CD-R was widespread, having only 3.5" floppies a Zip 100 drive, trying to look into how to move files from our old family computer to a new one.
I did find some sort of software at Best Buy or Circuit City, someplace like that, which used an A-A cable to directly connect two systems.
Yep. These were a stopgap in the days when normal users could not be expected to have a functional home network of any sort. Those were indeed active devices, and had a lump in the middle of the cable that basically amounted to an integrated USB hub.
Why not a serial null modem cable and zmodem?
micro-B SuperSpeed is always a good one to surprise people with.
I have a portable hard drive that uses this. I haven’t bought a new cable yet, limiting me to USB 2 speeds. Bleh.
Using those now! Have 3 drives in a Storage Space, another for backup. (And offsite backups!)