> As for voltage - 5V is universal with USB Nitpick for interest's sake: apparently there's a new (2012) 'USB Power Delivery' spec[1] which specifies two new v

> As for voltage - 5V is universal with USB Nitpick for interest's sake: apparently there's a new (2012) 'USB Power Delivery' spec[1] which specifies two new voltage levels (12V & 20V) in addition to 5V, with higher current limits (2A at 5V, 3A at 12V or 20V for microUSB connectors). Obviously both ends (and the cable) have to support it; I don't know if anything actually does yet. [1] http://www.usb.org/developers/powerdelivery/ http://www.usb.org/developers/powerdelivery/