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I'm looking into using a USB 3.1 type-A port (ref: 632121300001) and its male counterpart that comes with a "PD DETECT" pin. I'm looking to make a USB-A to USB-C cable. I might be missing something really obvious but I cannot find anything in the USB-C specs about this. Those only ever mention 8-core cable assemblies for USB-A to USB-C.

At first glance, I thought this might just be a PD DETECT <> CC line, but the more I look around and the less it looks like it. Now I'm wondering if it's exclusively used for E-markers for PD. This would still make it a CC-related pin but would make it meaningless to connect it to an actual CC line for pullup/pulldown resistors.

What is the PD DETECT pin used for and how does it connect to a USB-C connector (if at all?)?

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That's an Type A socket with support for USB-PD. The sockets and plugs are slighly different to mark that they support USB-PD, i.e. can pass higher current.

It just has two extra features. It has a pin to detect if it has a plug inserted, and it can detect if a USB-PD A plug is inserted.

The plug insert detect pins 11 and 12 connect together when any plug is inserted, and pins 10 and 13 connect together if it is a PD plug.

Type-A PD plugs have slightly longer metal shells.

So it has nothing to do with USB-C and does not connect to any USB-C pin.

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  • \$\begingroup\$ Gotcha! Thanks! When it detects that it is a PD plug, how do the devices agree on what power is adequate? I'm having a hard time figuring out how this is used. My assumption was that both devices needed to communicate on PD AND the cable had to be able to demonstrate how much power it could support with e-markers. Not sure how either would be done here. \$\endgroup\$
    – D.Mill
    Apr 21 at 17:00
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    \$\begingroup\$ If I understood correctly, devices communicate over the VBUS supply wire if PD plug is detected The cables are already detected to be PD capable from the plug. \$\endgroup\$
    – Justme
    Apr 21 at 17:06

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