Android Enthusiasts Stack Exchange is a question and answer site for enthusiasts and power users of the Android operating system. It only takes a minute to sign up.
Sign up to join this community
I have a Samsung Tab E that only has one USB port.
Can I charge the tablet and have a USB keyboard attached at the same time?
I've tried a 3-way cable ( link to Amazon ) but it supplies power to the keyboard, not the tablet.
I've also tried using a USB hub I had lying around, but I couldn't get that to work either.
The most likely way to use a keyboard while charging on a single port device is to use a Bluetooth keyboard.
Failing that, you may need a different 3-way cable. The keyboard certainly needs power to operate (unless it has internal battery power), but a correctly wired 3-way cable should be able to both power the keyboard and charge the device. You can verify that there's voltage on the charge pins of the two USB connectors on the 3-way cable, with a meter and suitable fine probes -- though it's very possible that the device will refuse to accept charge if there's a data attachment on the USB port. You'd have to contact Samsung to verify that.
I contacted Samsung support and their answer was that the single USB port cannot be used for charging the tablet at the same time as providing a data connection.
There are three kinds of USB ports in use (before USB Type C)- data only, charge only and both data and charge
Quoting from How USB charging works
In terms of actual current (milliamps or mA), there are three kinds of USB port dictated by the current specs: a standard downstream port, a charging downstream port, and a dedicated charging port. The first two can be found on your computer (and should be labeled as such), and the third kind applies to “dumb” wall chargers.
Tablets are known to have any of these ports. The port you have for charging is a dedicated charging port (as I suspect ) and will not allow simultaneous data transfer. This is borne out by your observation that the keyboard is getting power when connected with a 3 way cable or even USB hub (more reliable for such requirements)
You can easily verify this by connecting a flash drive through an OTG cable and transfer files. If it doesn't work (as I suspect), you have your confirmed answer
It may turn out to be a futile attempt by introducing additional hardware to meet your goal if the port itself cannot support. You may like to first validate this by seeking a confirmation from OEM, in case my reasoning current appeal to you
