USB-C to USB-A won't work both ways?

Haoshiro

macrumors 68000
Original poster
Feb 9, 2006
1,893
6
USA, OR
I'm on a 16" MBP and trying to connect a USB-A hub with a USB-C to A cable but it will not power on or connect the hub.

I thought maybe I had been stuck with a charging-only cable so I bought a new USB3 cable with high speed data support and it still would not work.

If I use either the official or third part male USB-C to female USB-A dongle plus a USB-A cable the hub does work.

For further testing I took the C-2-A cable and connected the A end to the dongles in order to make a USB-C to C cable just to test.

If I connect the dongle end to the laptop the cable works fine (can charge a Switch, etc) but if I switch it and plug in the other end it no longer works. Essentially if the A end is connected to a source device (with or without a dongle) the other end functions. but if the C end is connected to the source (MBP) the cable(s) no longer function.

Is this a known issue or does anyone have insight on how I can solve this? Ultimately I'm trying to reduce cable clutter and I don't know why this would not work with known good cables capable of data transfer.

Any help/advice is appreciated. Thank you!
 

Saturn007

macrumors 6502
Jul 18, 2010
380
122
If I understand your situation right, the problem is that the USB C to USB A cable cannot power the USB A hub you have. Is that right?

I wonder if any of them work... It could be that there's not enough power transmitted to activate the USB hub.

What do the reviews of your hub say on Amazon?

Perhaps, you're stuck having to get a USB C hub with USB A ports.
 

Haoshiro

macrumors 68000
Original poster
Feb 9, 2006
1,893
6
USA, OR
Turns out you can't plug anything into it at all and it work.

If the C end plugs into the laptop then you plug something into the A end it doesn't seem to work. If I plug the A end to the laptop (using the A to C adapter) it will work.

I have a USB-A wall jack that I am wanting to connect directly to the laptop with as few of connections as possible.
 

xraydoc

macrumors demi-god
Oct 9, 2005
7,511
1,703
192.168.1.1
I'm on a 16" MBP and trying to connect a USB-A hub with a USB-C to A cable but it will not power on or connect the hub.

I thought maybe I had been stuck with a charging-only cable so I bought a new USB3 cable with high speed data support and it still would not work.

If I use either the official or third part male USB-C to female USB-A dongle plus a USB-A cable the hub does work.

For further testing I took the C-2-A cable and connected the A end to the dongles in order to make a USB-C to C cable just to test.

If I connect the dongle end to the laptop the cable works fine (can charge a Switch, etc) but if I switch it and plug in the other end it no longer works. Essentially if the A end is connected to a source device (with or without a dongle) the other end functions. but if the C end is connected to the source (MBP) the cable(s) no longer function.

Is this a known issue or does anyone have insight on how I can solve this? Ultimately I'm trying to reduce cable clutter and I don't know why this would not work with known good cables capable of data transfer.

Any help/advice is appreciated. Thank you!
USB-C to USB-A adapters are one-way devices. You can't flip the orientation.
 

jaytv111

macrumors regular
Oct 25, 2007
242
75
Your hub should have a USB-B port or it should have a USB-A integrated cable (only has the USB-A male plug). If it has a USB-B port, you can connect an appropriate USB-B to USB-C cable between the Mac and hub and it should work. You can find common USB-B to USB-C cable types here: https://www.belkin.com/us/c/smartphone-and-tablet-cables/

Or, you can go from USB-C to USB-A female and then a conventional cable to the hub if you do not have a USB-B port on the hub, or even if it does have a B port on the hub it still works with this adapter. The important part is that you must connect to the one and only one cable or port that was always meant to connect to the host (Mac). You cannot go USB-A male to USB-C male at all because the hub doesn't do that, and USB doesn't work like that.

It does sound like your goal is to cut the adapter middleman out of it, so if you do have a B port on the hub, then you can simply replace the cable with a new B to C cable. If you have an integrated cable in the hub, as I said before, then you can't replace that cable and instead you must use the integrated cable with an adapter, C to female A.

I have a USB-A wall jack that I am wanting to connect directly to the laptop with as few of connections as possible.
So, interestingly the new Macs can be powered by USB-A power bricks, but it's not a great idea with larger Macbooks. I tried it out myself and found that my 15" can be powered by a 12 watt brick over USB-A, but it can only slow charge the laptop and any kind of remotely heavy use will drain the battery faster than it can charge. You should use USB-C to USB-C and an appropriate power brick (with C of course) for the Mac at all times, unless there's an emergency like you lost your power brick and you need to charge (albeit very slowly).

I'm not sure what this has to do with the USB-A hub though (USB-A hubs never provide power to the host). IF you however are seeking a one cable solution with docking and power, then look into a USB-C dock or Thunderbolt 3 dock. They let you plug in a USB-C power adapter then supply power to the Mac over USB-C.
 
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