Does My Tablet Support USB Host?
While the hardware of your tablet might support USB host mode, there is every chance that the operating system doesn’t. As such, you might need to root your device. This depends entirely upon which Android tablet you are using, and which version of the operating system is in use.
For instance, if you are running an Android Honeycomb tablet, then you should expect the device to be capable of USB host mode. However, it may not be activated.
Conversely, there is less chance of a pre-Honeycomb tablet (for instance Android 2.2 Froyo) being suitable to host USB devices, although some of the small Archos tablets do feature this functionality.
Another thing to consider is the USB connector on your device. If you have a micro USB connector then USB host mode will not be possible without a special micro USB host cable; these are available for a few dollars on eBay.
Ultimately, however, if your device does allow you to connect USB devices such as keyboards and external storage, you might need to root the tablet in order to activate this setting feature.