USB splitter

[MikeK]

I just got one of these USB splitters.  It's not a hub, just a Y splitter...One USB-A male to two USB-A female.  One of the female connections does not appear to work.  If I connect, say, a mouse to the good female connector it powers up and works just fine.  If I connect the same mouse to the bad female connector it neither powers up nor works.

Am I missing something or is this as faulty as it appears?

[ataradov]

This is highly non-standard. There is no way this can work for communication.

How is this splitter advertised? Can it be power-only on one side?

Mouse may not indicate power if it does not see the data. Check connectivity of the splitter with a multimeter.

The diameter of the cable also looks different, suggesting one of them as power-only.

I found a bunch of listings for similar products, and they all have a note that one side is charge-only. It is crazy what kind of non-standard nonsense they can come up with.

[Ian.M]

Your mouse probably needs a USB host to initialise it before it turns on its LED.   Try it on a powerbank or USB charger, and I'll bet the LED doesn't light!

I'd bet there is no data connection to the 'bad' connector, as I doubt they've included a two port hub chip, and you haven't seen a new hub enumerate.  Odds are it is power only and will power a USB powered 'tchotchke' that doesn't need too much power just fine.   

 Of course its non-compliant as the 'good' connector will be wired straight through, so it cant negotiate for the extra power drawn by whatever you plug into the 'bad' connector, so even if not faulty, its defective by design!

[MikeK]

My fault for not reading the entire ad.

the other is only charging. Not Two are data transmission and charging.

So there is no USB splitter?  Only hubs?  Aren't USB host ports ganged together electrically?  I assumed I could connect keyboard and mouse to my RPi 3A+ (only one USB port).

[ataradov]

Nothing in USB is ganged. USB on a physical level is always 1:1 connection.

There are versions of a similar splitter with an active hub. They have a plastic molded box in the middle of the cable, but still more compact than a full blown hub.

Here is one example https://www.amazon.com/Splitter-Andul-Female-Extension-Adapter/dp/B07LF85BKP

[MikeK]

Great, thanks.

[c64]

It's probably a cable from external HDD. Quite common. One USB port is not enough for power, so they provide second connector to double the current

[james_s]

It's probably a cable from external HDD. Quite common. One USB port is not enough for power, so they provide second connector to double the current

No, this is backwards from that. This one has one male plug feeding a pair of female plugs, one of which obviously has to be power only. You can even see in the picture one of the cables is thinner.

[MikeK]

Yeah, I didn't even notice the difference cable thicknesses.