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A comment on Former student destroys 59 university computers using USB Killer device. Parent comment

Re:Former student destroys 59 university computers using USB... by michaelt on Friday April 19, 2019 @09:11AM (#19699283) 

  The problem is: optoisolators are very slow.
Many are but they don't have to be - an optoisolator is just a zero-length fiber optic cable. Ain't much higher bandwidth than a fiber optic cable.

Not saying apple laptops ever had optoisolated USB though.

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Re:Former student destroys 59 university computers using USB... by mindslight on Friday April 19, 2019 @11:50AM (#19700510)
IMHO the problem with isolating USB is the 480Mbit ("USB 2.0") bidirectional signal.

12Mbps/1.5Mbps is easy. ADI has an integrated magnetic isolator chip. For hobbyist use you can get this assembled on a board ready to use as an ebay special.

The 5Gbit of USB3 is two unidirectional links and so is also easy (monoprice and elsewhere sell optical USB3 cables).

And lest you think you'll isolate at 5Gbit and then use a hub to translate to 480, USB3 doesn't work that way - the backwards compatibility is provided by a complete USB 2 bus in parallel.

For general isolating (say an electronics workbench), it's easiest to consider the USB host floating (eg a dedicated bench computer), and rely on ethernet (T or SX) for the isolation.

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