我现在还没搞清楚这个兼容是指u*****2.0的外部设备可以兼容u*****1.1的pc呢,还是u*****2.0的pc可以兼容u*****1.1的外设?
Usually the answer to your question is both are ok.
If you read manual for USB 2.0 device, usually it is backward compatible with USB 1.1. That is, it can run at USB 1.1 speed if the other device it connects to can only take USB 1.1. Double check manual for sure.
That's the theory part. In reality it might be different. In my case, my hard drive enclosure(USB 2.0) only works on two of four USB ports at back of my PC. It doesn't work at all if it's connected to USB ports at front of my PC.