One of the chief benefits of Android is its support for add-on storage, yet surprisingly few of the latest Android smartphones and tablets include a microSD slot. My new Moto X, for example -- no slot.
The good news is that the operating system can still access external storage (as well as various external devices like keyboards and game controllers). The bad news is that not all devices come with the necessary hardware and drivers for this USB On-The-Go (OTG) capability. So how can you determine if yours does?
I tried it with the aforementioned Moto X, a Virgin Mobile ZTE-made Supreme, and a Google Nexus 10 tablet. I know from my own separate research that two of these support USB OTG out of the box -- the Moto and Nexus -- and USB OTG Checker confirmed that while correctly determining that the Supreme does not.
In other words, although some of the app's user reviews indicate it's not accurate, in my tests it went three for three. Your mileage may vary.
Fortunately, even if your device fails the test, you can still take advantage of USB OTG. Read my post on how to use external storage to expand unexpandable Android phones. Short version: root your device using the excellent Kingo Android Root utility, then grab an app that can "mount" external storage (I'm partial to USB OTG Helper).
If you've been able to run USB OTG Checker on your phone or tablet, share your results here (pro or con). And if you've found a better way to determine its OTG compatibility, feel free to share that as well.