switch usb port

[timo.knothe@emerson.com]

Hello,

i'd like to know, if it's possible to switch the power of an usb port on and off. I'd like to control an optical coupler. Thanks for answering.

Hallo,

würde gerne wissen ob ich mit LabWindows die Spannungsversorgung von einem USB-Port aus bzw. anschalten kann? Würde gerne mit der 5 V Spannung einen Optokoppler betreiben. Danke im Vorraus

[Gerryli]

Hi, Timo

 you may can use the data line to control the opto-coupler. for Vcc Line, i think it keeps on unless you shutdown the computer 🙂

B.R

Gerry 

[ngay528]

If you are connected directly to the computer (not a hub), you can "Dismount" the unit which may turn the power off to that usb port, although have not verified it fully.  There exists win api's for this as well as a program called deveject.exe that I like to use.

Else electrically, you could just disconnect the VCC and GND lines from the cable and power that off an external source.  and just tie a leaded resistor or something between the USB's VCC and GND to make it happy (that is if you need data communication).