Question: what is the difference between usb a and usb 3.0?
Answer: The A connectors still work properly so any 2.0 device with a 2.0 cable can be used with 3.0 ports or hubs. To sum up: USB 3.0 devices require 3.0 cables. USB 3.0 cables can be used with 2.0 devices and ports if the connector types fit (no B Male or B Micro connectors) but the transfer rate will fall back to 2.0.