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Forum NewBie Qn about Search & USB LoopBack

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  • Forum NewBie Qn about Search & USB LoopBack

    1. Searching the Forum

    Firstly, how the heck do you search for a particular topic. I can't find a search box etc like all other Forums I use.

    2. USB LoopBack Plugs & Mis-Wired Ports

    A problem with front panel devices & PCI slot sockets that connect to the motherboard is that motherboard pinouts can be different on different motherboards.
    At one time I had three different motherboards on my bench & the pinout was different on all three.
    Some bay devices & front panel connections use individual pin connections or 2x 4 pin connectors with a flying shield for the USB connector & there are USB 3.0 to USB 2.0 converters to allow incompatible motherboard headers to use unused USB port connectors on front panels & front bay devices.

    As a result of those issues, USB ports can be physically wired incorrectly.
    It is a real pain in the b... to plug a USB stick in & not have it work, not think about it & plug another in
    ... then it dawns on you that you have fried the diagnostic USB Sticks because of a mis-wired port.

    The USB LoopBack blurbs state: "USB 2.0 Loopback plugs are one of the fastest methods to diagnose, troubleshoot and load test your PC's USB functions" & "Active loopback plugs are the quickest, most effective way to verify that a PC's USB ports are working correctly" and state that they will check if cables are wired correctly but I can't see if they actually check the wiring of the outlet or if they are protected against incorrect pinout or say the extra high USB 3.0 voltage on any data pin.

    Can the LoopBack connectors diagnose incorrectly wired ports?
    Can they survive all combination of miswired port & can a USB 2.0 LoopBack Plug survive being plugged in to all combination of miswired USB 3.0 port with the extra voltages that may be involved?

    I just fount the "USB Port Power Tester" at & was wondering if I need to get one of them (or something similar) as well as your product or if the PassMark USB LoopBack will provide those functions as well. Your blurb doesn't really seem to cover that issue & I know from experience that it is always lurking.


  • #2
    There is a search box top right of the web page.

    No, the USB2 plug can't detect all possible bad wiring and bad voltages. It is possible to blow it up.

    The USB3 loopback plug has better protection however. See this page for details,
    It is still possible to blow it up however. There are 10 wires for USB3, so it isn't possible, at reasonable cost, to protect against all possible bad permutations of bad wiring and high voltages.