this post was submitted on 10 Oct 2023
324 points (95.3% liked)
Asklemmy
43822 readers
891 users here now
A loosely moderated place to ask open-ended questions
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- !lemmy411@lemmy.ca: a community for finding communities
~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
It’s not hard to imagine a product that would require one, though. It’s how every phone charging cable works, just with a different size male USB on one end.
No, it's exactly not how every phone charging cable works, at least not for non USB-C cables.
Pre-USB-C cables are explicitly unidirectional. In USB there are 'hosts' (usually computers) and 'devices' (flashdrives, camera's, mice, keyboards, etc.). The host side always has a female USB-A connector, a device either has a female USB-B connector (if it's intended to be used with a cable), or a male USB-A (if it's intended to be plugged in directly into a host, like a flash drive). A real, standard-conformant USB cable can only go from USB-A male to USB-B male (with the addition of USB-C, it can also go from A-to-C, from C-to-B, or C-to-C). Never A-to-A or B-to-B, extension cables (male to female) of any type, A, B or C, are not allowed either.
USB was specifically designed like this so you can never connect a device to a device or a host to a host.
On the host side, you pretty much only see full size USB-A ports. On the device side there are 3 common types of USB-B ports: standard size (you can for example see these on printers and scanners), mini-USB-B used a lot on older phones, and later micro-USB-B. On each side the male part is on the cable, the female part is on the host or device.