Long ago I was reading about USB design and don't get one thing.
One advantage of USB is that it has optron decoupling and this makes connection/disconnection of powered on devices safe. This implies that direct (no decoupling) connection (as in older interface ports design) is somehow unsafe.
I read somewhere that some transient processes can happen on connection/disconnection and damage the circuits when there's no decoupling but can't find a simple explanation of what exactly might happen.
What exactly happens on connection/disconnection of powered devices without decoupling? What's some simple example of how damage occurs?