5 ms·

USB C has confused me for the same reason. I read often about how there is no expectation that two USB-C cables/ports will work together. Why design them to fi

USB C has confused me for the same reason. I read often about how there is no expectation that two USB-C cables/ports will work together. Why design them to fit together if they won't always work right?

weberc2 7y ago
> Why design them to fit together if they won't always work right? I too don’t understand dynamic typing. ;)
jakobegger 7y ago
Because it's useful to have a bunch of multi-purpose ports on a computer. You can attach a mouse, a keyboard, a printer, a hard drive, a screen, a dock, a charger, or whatever you want, all to the same port. In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box.
- johnbrodie 7y ago
  It's not the initial cable that's the problem, it's those that come after. My wife wanted a charger with a longer cable for her phone. We need it to be able to fast charge, which is called a variety of different names on both the phone and charger sides. Can I get the $10 charger, or do I need the $40 charger the size of the MBP charger? We ended up just biting the bullet and getting one of the more expensive, MBP-charger-shaped chargers, since I have laptops that use USB-C - but it was a confusing mess, and I still wasn't really sure fast charging would work on her phone till I plugged it in the first time.
  - silversconfused 7y ago
    You needed a $5 AC power extension cord.
    - michaelt 7y ago
      Carry around a 3,000 watt mains extension, because someone decided making USB C cables all support 100 watts was just too demanding, eh?
      - silversconfused 7y ago
        Well sure if it's for a airconditioned-hottub-phone, but I'm pretty sure a small 600 watt cable would be more cost effective here.
      - jakobegger 7y ago
        100 watt USB cables are a bit thick and unwieldy since they need to support a current of 5A. They also need better insulation, since they use a higher voltage (up to 20V). If your phone can only charge at 10 watt (5V / 2A), why would you use a stiff, heavy 100W cable to charge it?
- stordoff 7y ago
  > In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box. Which is fine, until you need you need a new cable. When I lost the cable for my phone, finding a cable I could trust was a pain.
cesarb 7y ago
> Why design them to fit together if they won't always work right? USB-C is designed for graceful degradation. There are two main types of non-captive cables: USB 2.0 only and USB 2.0 plus USB 3.x. Hosts and devices have to support at least USB 2.0, so if you try to connect two USB 3.x devices with a USB 2.0 only cable, it'll fallback to a USB 2.0 connection. There are two main current levels: 3A and 5A. Cables which can carry higher power have a small chip describing this fact; if the chip is missing, the power source will limit itself to 3A. Then there are the alternate modes. If you try to plug a device which only understands an alternate mode (for instance, a DisplayPort adapter), and the host doesn't understand that alternate mode (or can't understand it, like in the case of a USB-A port with a USB-A to USB-C cable), that device will instead appear as an USB 2.x device (the "billboard device"), which the operating system can use to show an error popup. And so on. At every corner of the spec you can notice an interest in making it degrade gracefully. Of course, that can only work when the manufacturers follow the spec correctly.

weberc2 7y ago

> Why design them to fit together if they won't always work right? I too don’t understand dynamic typing. ;)

jakobegger 7y ago

Because it's useful to have a bunch of multi-purpose ports on a computer. You can attach a mouse, a keyboard, a printer, a hard drive, a screen, a dock, a charger, or whatever you want, all to the same port. In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box.

johnbrodie 7y ago
It's not the initial cable that's the problem, it's those that come after. My wife wanted a charger with a longer cable for her phone. We need it to be able to fast charge, which is called a variety of different names on both the phone and charger sides. Can I get the $10 charger, or do I need the $40 charger the size of the MBP charger? We ended up just biting the bullet and getting one of the more expensive, MBP-charger-shaped chargers, since I have laptops that use USB-C - but it was a confusing mess, and I still wasn't really sure fast charging would work on her phone till I plugged it in the first time.
- silversconfused 7y ago
  You needed a $5 AC power extension cord.
  - michaelt 7y ago
    Carry around a 3,000 watt mains extension, because someone decided making USB C cables all support 100 watts was just too demanding, eh?
    - silversconfused 7y ago
      Well sure if it's for a airconditioned-hottub-phone, but I'm pretty sure a small 600 watt cable would be more cost effective here.
    - jakobegger 7y ago
      100 watt USB cables are a bit thick and unwieldy since they need to support a current of 5A. They also need better insulation, since they use a higher voltage (up to 20V). If your phone can only charge at 10 watt (5V / 2A), why would you use a stiff, heavy 100W cable to charge it?
stordoff 7y ago
> In my experience, finding the right cable has never been an issue. All the USB-C devices I've bought came with a suitable cable in the box. Which is fine, until you need you need a new cable. When I lost the cable for my phone, finding a cable I could trust was a pain.

cesarb 7y ago

> Why design them to fit together if they won't always work right? USB-C is designed for graceful degradation. There are two main types of non-captive cables: USB 2.0 only and USB 2.0 plus USB 3.x. Hosts and devices have to support at least USB 2.0, so if you try to connect two USB 3.x devices with a USB 2.0 only cable, it'll fallback to a USB 2.0 connection. There are two main current levels: 3A and 5A. Cables which can carry higher power have a small chip describing this fact; if the chip is missing, the power source will limit itself to 3A. Then there are the alternate modes. If you try to plug a device which only understands an alternate mode (for instance, a DisplayPort adapter), and the host doesn't understand that alternate mode (or can't understand it, like in the case of a USB-A port with a USB-A to USB-C cable), that device will instead appear as an USB 2.x device (the "billboard device"), which the operating system can use to show an error popup. And so on. At every corner of the spec you can notice an interest in making it degrade gracefully. Of course, that can only work when the manufacturers follow the spec correctly.