Q: I have a usb to ps2 adapter and my mp3 player charges on it ( I plug the mp3 player into the usb part, then plug the adapter in) Is there a chance of destroying the mp3 player if I do that, or does usb and ps2 provide the same voltage? (yes, it charges). I don't want to destroy my mp3 player, but I want to free up my only usb port for other stuff that needs more than charging. Please only answer my question if you know what you are talking about, and understand what I mean. Thank You!
A: Maybe. It's risky because PS2 ports are only rated at 100 mA. USB ports are also rated at 100 mA prior to the system "turning the device on" after which some devices may draw up to 500 mA. If the device draws too much for the system to handle, the USB specs require the host to shut down the port in a recoverable way. The problem is that PS2 ports don't always shut down in a recoverable way if you draw too much current. Common designs simply had a little fuse on the motherboard, and if you pop that, your PS2 port is now dead. So, if you don't actually plan to use that PS2 port, or if you know what your charging current is, or if you know that you can charge safely without the USB system turning your device on, then you are probably OK. But it's a risk.