4 ms·
"Traditional" USB does that: USB-A ports source power, USB-B ports sink power. (Also, USB-A ports are always towards the host, which controls the bidirectional
by cesarb 8y ago
"Traditional" USB does that: USB-A ports source power, USB-B ports sink power. (Also, USB-A ports are always towards the host, which controls the bidirectional serial link.) The standard cable has a USB-A plug on one end, and a USB-B plug on the other end. There can be no USB-A to USB-A (or USB-B to USB-B) cable, since they're forbidden by the standard, so you can't connect two sources (or two sinks) together.
And of course it didn't work: there are many standard-breaking USB cables with identical plugs on both ends, and standard-breaking devices which require them.
- DSMan195276 8y agoThat's not quite what I described. With my design either port can source or sink power, they just do it on opposite pins. And it wouldn't be USB-A vs USB-B, but male vs female So for USB, you would need a 5-pin port, where two are devoted to power. And both USB-A and USB-B would have the same wiring, but male ports source and supply on opposite pins as the female ones. Then M-M or F-F cables crossover the power lines.