Connect a passively powered usb hub into a self-powered one, what happens?

[tundrawolf86]

Hi, I just got a 13 port USB 2.0 hub with its own power supply. I have saturated it already with flash drives, bluetooth dongle, micro/mini cables, external hard drives, scanner, printer, and external DVD writer. I didn't want any of these things drawing power from my laptop motherboard.

Now, I have one port left. If I plug a passively powered hubman into it, the hubman draws power from the powered hub and not the motherboard, right?

Can someone explain to me the basic principles of drawing power through USB ports? Thanks.

Also, is there a certain order in which I should be powering things up and shutting them down? When I start my laptop, I power up the hub first (reasoning that powering up the laptop first would cause the things to draw power from the motherboard until I hit the hub power switch). When I'm ready to power down, I turn the hub off first and then the laptop. That's what you're supposed to do, right?

 

[oczdude8]

the usb hub is most likely only connected by the 2 middle pins on the usb cable. USB cable has 4 pins inside, +5V,ground, Data+, data-. for a powered hub, it would only be connected by the data+ and data-, so it is completely separated from your laptops USB power.

http://www.google.com/imgres?imgurl=http://image.pinout.net/pinout_USB_files/pc_usb_connectors_pinout.png&imgrefurl=http://image.pinout.net/pinout_USB_files/&h=431&w=512&sz=19&tbnid=4_384cEs6i81HM:&tbnh=94&tbnw=112&zoom=1&usg=__hiN1MuPgl0_BcBazTUg3i9mz7Yw=&docid=vhY5nfOC2XiscM&sa=X&ei=ig5gUsvBLc7i4AOG-IGABg&ved=0CD0Q9QEwAw

I would always just turn on the hub before the laptop and turn it off after the laptop, just as a precaution, but it doesn't really matter.