Wednesday, 3 October 2012


I have just found out about a thing called USB OTG or USB on-the-go. USB connections use the concept of "master" and "slave". Suppose you plug a printer into a computer; the computer is the host and the printer is the attached device, controlled by the computer. Or I might plug my Nexus 7 tablet into my computer, and again the computer is in charge. But with USB OTG something that's usually a "slave", like a phone or my Nexus 7 tablet, can become a "master" or host for another USB device. This would usually be either an input device, like a keyboard, or a storage device, like a USB pen or an SD card in a USB reader.

The upshot of this is that with a USB OTG cable, which cost me about £1.50 off of amazon, I was able yesterday to plug an old USB keyboard into my Nexus tablet and type away merrily with no setup whatsoever. As I understand it the Nexus 7 automatically supports USB OTG for keyboard and mouse. In order to use a USB pen drive I had to download an app. I downloaded this free picture viewer app by Homesoft, and it worked well, so I think I will buy this app which allows you to use other forms of media. You can't write to the USB storage device, only read from it.* Also I haven't tested how well it works with material left in situ on the USB device. Nonetheless this is a very cheap solution to one criticism levelled at the Nexus 7, that it has limited storage and you might not be able to fit onto it all the films you wanted to watch on holiday, for example.** I have all my work ever on a 500Gb portable hard drive, and depending on how easy it is to navigate this could be a much better solution than trying to get it all into the cloud and then relying on having internet access wherever I go. Hurray!

* But you can write to a USB device using an OTG cable from the Nexus 7 if you root it, something I don't really want to do.

** Charlie Stross has a more expensive but more interesting solution.


  1. I've read online that an external HD will need its own power-source. (Which rules out my external HD.) But apart from that, I like the concept a lot.

  2. I hadn't thought of that -- bother, that will need some consideration. Does flash memory use less power? Adrian has just put a 256Gb SSD in his Mac.