# How do I deal with multiple, separate shields?

With HDMI or USB3.0/3.1, a cable assembly, in addition to the main braided shield, has multiple separate shields for each differential pair, here an example of a USB3.0 cable:

The inner shields are connected to the GND_Drain pin on the plug:

With HDMI, it's even more complicated. There, every single one of the four differential signal pairs has its own ground connection on the plug:

How am I supposed to connect these additional ground connections together on a device? Coming from this question, the outer shield could be connected to power ground directly - a few more options are outlined here - and should be connected to the case of my device if that's made from metal. That's easy enough, but what about these additional connections? Would connecting them directly to the outer shield reduce their effectiveness?

• What do you mean by "deal"? usually you don't care how the cables are made up, you just plug them into the socket you have on your device, and then you "deal" with that socket... – PlasmaHH Nov 16 '16 at 12:21
• I meant how should I connect them together on the PCB. Sorry, I'll update the question to reflect that. – iFreilicht Nov 16 '16 at 12:23
• Since you have a photo showing how the cables are built, you probably noticed all these shields are touching themselves all the way through the cable. Therefore, can you please explain why you think an additional connection, on the PCB, of the inner shields with the main shield would reduce their effectiveness ? – dim Nov 16 '16 at 13:17
• @dim That's not what I'm seeing. There is a thin, blue, presumably insulating film around these inner shields, which I suspect is done for a reason. – iFreilicht Nov 16 '16 at 13:24
• @iFreilicht That is right, there is a blue side. But I don't think this it is really efficient as an insulator. It is easy to make the test, however: take a brand new cable, a continuity tester, and check whether the various shield are shorted together or not. – dim Nov 16 '16 at 13:32