@tubetime through the skin of the device user. So, I guess that would be a very low value capacitor with extremely high ESR?

@tubetime capacitor (and high-value resistor in parallel) for ESD protection: the shield is a touch-point and is susceptible to contact ESD strikes. Ref: Microchip AN2587 at https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ApplicationNotes/ApplicationNotes/00002587A.pdf

@tubetime I'd say through a resistor, something like a 10k resistor. Not sure why you'd add a capacitor; I'd guess the shield itself has enough parasitic capacitance to hold an ESD spike. And I don't understand analog electronics enough to know about the inductor, but I can see a case for it.

Did once encounter a USB plug converter that just didn't connect GND, so the only GND we got was through shield ground...

@tubetime always nail it down. The device isn't expected to have any other earth, and shield isolation isn't needed for signal integrity

@tubetime I have no idea about this, as I am a software person, but find this topic extremely interesting. I hope this will be resolved!

@tubetime Device side float, host side connect straight to GND. You have a ground loop otherwise. The shield is just to keep stuff off the cable.
And now I'm filled with doubt 🥺

@tubetime directly - ground's gotta be grounded!

(well, unless you don't have a truly grounded wire - like plastic encoated device with only two-poled power supply)

@tubetime I think there are two possible answers: directly and capacitor. Directly might be preferred for most applications, but it creates a ground loop that might be problematic in some applications. If that is the case, a capacitor might help. I usually put a 0603 footprint to assemble a 0 ohm resistor, that can be replaced by a capacitor if needed.

@tubetime direct connection. I used to use a 1nF // 1Mohm connection, but changed to direct after reading an application note or blog. Can’t remember where I read it.

@tubetime where is drain resistor..

@tubetime If it is a Type-C connector, connect shield directly to GND because the spec says to. If it is a host, connect shield directly to GND because the spec says to. If it is neither, you have options, but lately I prefer direct connection because it is simple, easier to pass ESD testing, and has become the norm since Type-C.

@tubetime I voted capacitor but in reality it is a parallel RC combination with 1 MΩ

edit: Justify it… I'm not 100% shure but I think the reason was grounding the device's case this way enough against static electricity but not providing a real DC-path to prevent ground-loops (host grounds the shield directly, device never).

src: some friend at C3PB explained this as the ultimate solution to me

so the correct answer is that *it depends on your system grounding strategy* but the most-often-correct answer is to tie them directly together. particularly if you're a hobbyist type, just tie them together and don't worry about it. but if that's not enough for you, continue reading...