Everyone knows their smartphone has a USB port on it, but most people just assume it’s for charging and connecting the phone to their computer. What they don’t know is that many (though certainly not all) smartphones support something known as OTG. This acronym stands for “On the Go” and it allows the user to connect a variety of standard USB devices to their phones. These include thumb drives, keyboards, mice, and external hard drives (with a caveat or two). Sadly OTG is not support by iOS, so even if the iPhone did have a USB port, you couldn’t use it anyway.
OTG cables are very inexpensive, ranging in price from as low as $1.67 (if you order one from Hong Kong) or up to $5 to $10 if you buy one at a local bricks-and-mortar store. They are usual very simple devices with a Micro USB plug on one end and a standard USB socket on the other. If your phone (and version of Android) supports OTG, then all you have to do is insert the adapter cable into your phone, and then plug in whatever USB device you want into the other end.
If you insert a mouse, a MOUSE POINTER will actually appear on your screen. Many people find that very surprising, as they had no idea there was actually mouse pointer support built into Android. You can now mouse around your screen and click where you would otherwise have touched the screen. A keyboard doesn’t produce any indication that it’s there, but if you are anywhere that needs text input, you can’t just type on your full-sized USB keyboard. Both the external and internal keyboards work at the same time.
When a Thumb Drive is connected, Android will automatically open File Explorer, allowing you to copy and paste to or from the thumb drive. Depending upon the app you use, it might even be able to directly access the files on the thumb drive without having to copy them first. You can also connect hard drives, even those that rely on the computer for power.
The only caveat is that Android doesn’t presently support NTFS, exFAT, or HFS+. The drive must be formatted in FAT32. However, if you have a rooted phone, there are free utility apps that run in the background and add support for NTFS, exFAT, and HFS+. The...
one I use is Paragon, which is available on Google Play free-of-charge. I routinely connect a 2.5-inch Seagate Free Agent GoFlex 500 GB hard drive (which is formatted in NTFS) to my Galaxy S4.
Another advantage of apps such as Paragon is that it works with internal MicroSD cards as well. Most phones don’t support 64 GB cards because they can’t be formatted in FAT32. With that limitation removed it’s possible to format a 64 GB card in NTFS and use it in the phone as though it were natively supported.
If you’d like to connect multiple USB devices at the same time (say a mouse, a keyboard, and a hard drive) you can do this by simply using connecting a standard USB hub. If your phone also supports MHL (which allows the connection of an MHL-to-HDMI adapter, which in turn allows you phone to be connected to an HDMI-compatible monitor or TV) the adapters usually include a pass-through USB port so that you can still connect USB peripherals.
This means you can have the full non-mobile experience, even with a smartphone. Just connect an HDMI monitor, a keyboard, a mouse, and a FAT32 external hard drive and you have yourself an Android-based desktop computer.
For those with rooted phones, you should also know that TWRP recovery natively supports OTG. This means you can write your Nandroid Backups directly to an external drive. You can even restore your phone directly from these external drives as well. This is extremely useful on the ever-increasing number of phones that no longer support MicroSD memory expansion. Saving a backup to the internal memory of a phone makes about as much sense and leaving your spare car keys IN THE CAR.
Finally, 2014 should be the year you’ll see a lot more thumb drives that internally support OTG and can be plugged directly into your smartphone. I’ve included an example in the picture below. The drive is made by Transcend.
With the ability to connect such peripheral devices to your phone (thumb drives in particular) you can do much more with your mobile device than you ever thought possible.