Suck it micro USB, mini USB, and lightning! 🪫🔋

  • dual_sport_dork 🐧🗡️@lemmy.world
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    4 days ago

    USB-A to A cables aren’t common

    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…

    • poweruser@lemmy.sdf.org
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      3 days ago

      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

    • Kazumara@discuss.tchncs.de
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      3 days ago

      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

      • Damage@slrpnk.net
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        3 days ago

        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

    • AnyOldName3@lemmy.world
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      3 days ago

      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.

    • halcyoncmdr@lemmy.world
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      3 days ago

      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.

      • dual_sport_dork 🐧🗡️@lemmy.world
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        3 days ago

        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.