3 ms·

The standard absolutely needs to support the ability for computer and peripherals to detect what kind of cable is connected ... then we need consumer level impl

The standard absolutely needs to support the ability for computer and peripherals to detect what kind of cable is connected ... then we need consumer level implementation at the os to tell people when their cable is insufficient for the task they are trying to accomplish — with this, bring on all the cost saving measures for cables. Without it — fucking idiot standards committees can go rot in hell for the blight they wrought upon the world ...

cesarb 7y ago
> The standard absolutely needs to support the ability for computer and peripherals to detect what kind of cable is connected The USB-C standard has always had that ability. There's a pair of pins on the connector dedicated to that. On a basic USB-C to USB-C cable, the first pin of this pair is connected to the corresponding pin on the other end, and the second pin is left unconnected; on an USB-C to USB-B or USB-A cable, this first pin is connected through a resistor with a specific value to the VBUS or GND pin (which one depends on the connector type); and on a more advanced USB-C to USB-C cable, or on an adapter to something like DisplayPort, the second pin is also connected, to a chip which informs the computer about the cable's extra functionality (and also negotiates the alternate mode in case of an adapter). The device on either end of the cable uses that pair of pins to: negotiate which end will initially be the "host" and which one will be the "peripheral"; detect when the cable is inverted; ask the cable about its capabilities; ask the other device to increase the power or change which device is supplying power; negotiate alternate modes like DisplayPort; and a few other functions. The only thing these pins aren't used to, as far as I know, is to distinguish between an USB 2.0 and a basic USB 3.0 cable; instead, the same method as the older USB-A or USB-B plug is used.
JohnFen 7y ago
> then we need consumer level implementation at the os to tell people when their cable is insufficient for the task they are trying to accomplish The need for that alone is a big sign that the standard is flawed from a user perspective. Ideally, it should be impossible to use the wrong cable for a task. Traditionally, this is done by making the shape of the connector different.

cesarb 7y ago

> The standard absolutely needs to support the ability for computer and peripherals to detect what kind of cable is connected The USB-C standard has always had that ability. There's a pair of pins on the connector dedicated to that. On a basic USB-C to USB-C cable, the first pin of this pair is connected to the corresponding pin on the other end, and the second pin is left unconnected; on an USB-C to USB-B or USB-A cable, this first pin is connected through a resistor with a specific value to the VBUS or GND pin (which one depends on the connector type); and on a more advanced USB-C to USB-C cable, or on an adapter to something like DisplayPort, the second pin is also connected, to a chip which informs the computer about the cable's extra functionality (and also negotiates the alternate mode in case of an adapter). The device on either end of the cable uses that pair of pins to: negotiate which end will initially be the "host" and which one will be the "peripheral"; detect when the cable is inverted; ask the cable about its capabilities; ask the other device to increase the power or change which device is supplying power; negotiate alternate modes like DisplayPort; and a few other functions. The only thing these pins aren't used to, as far as I know, is to distinguish between an USB 2.0 and a basic USB 3.0 cable; instead, the same method as the older USB-A or USB-B plug is used.

JohnFen 7y ago

> then we need consumer level implementation at the os to tell people when their cable is insufficient for the task they are trying to accomplish The need for that alone is a big sign that the standard is flawed from a user perspective. Ideally, it should be impossible to use the wrong cable for a task. Traditionally, this is done by making the shape of the connector different.