Apple USB-C Cable Not Recognized By what cable

[BanditoB1]

I have a couple of Apple USB-C cables that came with a device or an accessory but, unfortunately I don't know which ones, they are not recognized at all by what cable. It will show up if I plug in a USB device with it and it is listed as a slow USB device or charge-only cable at USB 2.0 only (480 Mbps).

Is not detecting this type of "dumb" cable when plugged in on its own the expected behavior?

Thanks for any insight that you can supply.

[darrylmorley]

Expected, yes.

A USB-C cable is only visible on its own if it has an e-marker chip inside. That chip is what answers when the port asks "what are you?". Your Apple cables are the plain USB 2.0 charge-and-sync ones (iPhone, iPad, Watch boxes), which have no e-marker, so both CC pins stay open, the port controller never registers a connection, and macOS reports the port as empty. WhatCable can only show what the Mac reports.

Put something on the far end and the port wakes up, which is exactly what you saw: USB 2.0, 480 Mbps. That's the cable's real spec, so nothing is being missed.

Worth knowing for the other direction too: the e-marker chip runs off VCONN, a small power rail the Mac feeds into the cable, and only answers a Discover Identity request. Some Macs read a marked cable straight away when bare, others wait until there's a real partner to negotiate with. So if an e-marked cable reads as basic when bare, plug something in at the far end and check again. Both points are in the Caveats section of the README.

[BanditoB1]

Thank you so very much, Darryl!

I love learning about new things and was aware of the differing USB-C cable types, but actually being able to see what the computer sees is quite fascinating. I have many more cables to test, so will see which brands are actually meeting their specs and which ones don’t.

It is a bit surprising to me that Apple’s basic cables don’t have an e-marker chip. That seems unusually cheap for them, but I suppose since it really is only the most basic of cables, there really isn’t any need to add the chip to it.

Thanks for creating a useful and fun application and sharing it with us. It is much appreciated. I’m going to switch to the Pro version to send a little “love” your way.

[darrylmorley]

Glad it was useful.

On Apple being cheap: the e-marker only earns its keep above 60W or above USB 2.0 speeds. A charge-and-sync cable needs neither, so leaving the chip out is the spec working as intended rather than a corner cut. And in my experience those basic Apple cables still hold up better than the cheap Amazon ones, to be fair.

If you turn up a cable that reads oddly (claims more than it delivers, or comes back blank when it shouldn't), there's a "Report this cable" button in the app. Those reports feed the cable database on the site, so the odd ones are genuinely useful.

And thanks for going Pro. Much appreciated.