Wikipedia:Reference desk/Archives/Computing/2019 October 18

= October 18 =

micro-usb vs usb-c
Why is micro-USB getting a bad rap these days? Is usb-C actually somehow better? I've been annoyed to see more USB-C stuff without good reasons, since the famous Benson Leung cable tests showing crappy USB-C cables damaging his equipment. Both types seem mechanically unreliable due to trying to make the connectors too thin. But, fast charging (15 watt Qualcomm Quickcharge) on micro USB seems to work fine. I thought the idea of "universal" was to settle on one thing and stick with it, like the 3.5mm universal audio jack... oh wait. Anyway I don't see why they keep changing these damn connectors and wish they would stop. Thanks. 173.228.123.207 (talk) 00:48, 18 October 2019 (UTC)


 * I agree. And why do printers need their own special USB connector ? There are way too many USB connector types. SinisterLefty (talk) 02:12, 18 October 2019 (UTC)


 * There's no such thing as a special USB connector for printers. Type B sockets are intended for devices and AFAIK this was part of the original USB1.0 spec. While printers may be the most common devices which use type B, prior to the adoption of mini then micro B; hubs, hard disks, card readers, satellite receivers and I'm sure other devices had standard type B sockets. Some had type A sockets, but this is non compliant. Likewise cables with type A on both ends aren't compliant and it does carry some risks, e.g. plugging a computer into itself let alone some other host could damage something. (There were special cables which were not simple A to A but instead had a network adapter or similar built in to allow connecting 2 computers to each other. I believe these were okay because they properly presented a device to both ends.) Most of these devices moved to mini and then micro as these became widespread but printers never other probably in part because there was no size reason to do so. Still even in the early 2010s, it there were some devices e.g. hubs on monitors, some satellite receivers which used standard type B as well so it was never a "special USB connector" for printers. AFAIK, mini and then micro came about because standard as too big then mini was too big. BTW, as I said below a key point of type C is you don't need any "special" USB connector any more. There is only 1 for everything. Nil Einne (talk) 13:25, 18 October 2019 (UTC)


 * USB-C connector is much more than just old good USB. It can carry various signals in various formats. Ruslik_ Zero 11:34, 18 October 2019 (UTC)


 * TL;DR most standards can't last for ever and there's often a reason to move on to something which is partly incompatible. When this happens, it's annoying in the interim. Clearly for a bunch off reasons, those in charge felt it was time to move on even if you don't agree. In relation to the original comment, I'm not sure if there is some confusion but the cable problem first highlighted by Benson Leung has nothing do with being too thin or anything like that. It's because people making the cables didn't properly follow the standard in adding the correctly sized pull up resistor. While there I'm sure there is much debate on the wisdom here, there are reasons why it's part of the standard.  Particularly now after much attention, I strongly suspect that a bunch of manufacturers do it intentionally because while potentially dangerous, it has advantages. If you use the wrong size pull up resistor, the device may try to draw 3A or 1.5A (depending on what you choose). This can be dangerous if the supply device (power bank, charger, etc) cannot support such a current draw, but OTOH the customer often doesn't understand or they don't care. Instead they see with your cable the device nearly always charges at high speed no matter what you connect it to. Very rarely the supply device may shut down or of course blow up or suffer obvious damage or otherwise have a clear sign of problem but I think this is rare. And heck in some cases the person may not know what happened.  By comparison, with your competitor's cable the device often charges at low speed because it refuses to draw a higher current. Whether because the supply device cannot support a higher current (and many do not support 3A; 2.4A was often the highest in part because it was what Apple supported). Or because the device and the supply device don't have the same signalling standard so the device doesn't know it can draw a higher current.  It's also worth remembering that this is primarily a problem with adapter cables. A type C to type C cable could still be potentially dangerously defective, as pretty much any cable, but it's a lot harder. (So largely an interim problem.)  In addition to RuslikZero's good point, a key aim of USB type C was to move away from all the different sizes. In the long term, everything could have type C, whether hard disks, mice, keyboards, USB memory stick, whatever. It's true that in the interim it sucks and for a variety of reasons most computer like devices only use type C for their super speed ports and have normal type A ports for their other ones; and mice and keyboards and so for this and other reasons mice and keyboards and other such devices also still don't generally have type C. Simpler devices like phone and tables only have 1 or 2 ports and these are generally type C regardless of the speed. (And many still provide chargers with standard type A ports even if their device has a type C port, relying on a standard type A to type C cable.)  Which actually moves on nicely to another point. As evidenced by the single standard, type C also means that while there is still a host, the clear distinction between host and device is less clear. Unlike with type A, plugging a host into itself or some other host should be safe. (Nothing may happen, but it's still safe.) See e.g. [//electronics.stackexchange.com/questions/255684/connecting-two-usb-c-hosts-what-happens].  Together, this also simplifies connecting devices to devices which can be hosts. For example, many Android phones support USB memory stick, USB keyboards, USB mice, USB hubs etc but with micro type B you need a simple/passive USB to go adapter to be able to plug them in. With USB type C, you can just plug your USB memory stick into your phone and it works. Likewise, while some older larger tables had standard type A ports, most tables have also moved away from that especially 7" ones which are after all not that much bigger than some phones. As implied before, they just have 1 or 2 type C ports.  As also implied before, USB-C also allows super speed in a small footprint. Micro USB A may be small, but not when you want super speed support. Have you never seen a modern portable or external hard disk before connector? Admittedly the super speed issue does bring up 1 point sort of touched on earlier. While the connection may be universal, the cable and ports are not. I mean sure any compliant cable should allow you to connect any device USB type C device to any host, the host may not support super speed or the cable may not so you're not guaranteed to get super speed, something likely to cause confusion.  USB-C is also reversible, something which seems to have been in demand after Apple's Lightning.  BTW, Qualcomm Quickcharge is not universal. It's Qualcomm proprietary standard. There is USB power delivery although that has been a bit of a mess. USB-C means 3 amp should ideally be widely supported although it's true many are still using their own proprietary protocols instead. Still, it does seem many do support simple 3 A USB type C even if it isn't what they actually use with their own chargers and power banks, meaning a greater level of interoperability.  In addition, while many short USB-A to micro USB B cables can handle higher currents, not all can and longer cables are even more of a hit and a miss. There is potentially nothing wrong with such a cable, they are not required to support higher currents. While it's true there are many crappy USB-C cables as well as mentioned before, such cables are clearly non compliant. So in countries with decent consumer protection laws, you'd generally be fully entitled to expect the cable to be replaced or refunded and probably any damaged caused by it covered.  Nil Einne (talk) 13:25, 18 October 2019 (UTC)


 * Nil, you wrote "tables" 3 times when I assume you meant "tablets". Maybe a rogue spellchecker ? SinisterLefty (talk) 17:31, 18 October 2019 (UTC)