In this tech-savvy era there is an ever increasing anticipation for devices that are able to cope with the basic technological computer-based uses like browsing the internet and transferring files across devices. There is also the increased need to improve storage as to allow for vast storage in small devices. From the use of traditional floppy diskettes to compact disk we are now in USB era. Use of memory sticks is common now-a-days for storing and transferring files between different electronic devices like laptops, cameras, phones, tablets and PCs.
Android USB host is device that allows you connect with storage devices like flash drives and phones; and also with HDI (Human Interface device) like the keyboard and the mouse. This device enables you to browse and even import photos from a camera to your phone, copying files onto a USB memory stick attached to your tablet.
How then can you know that my device has Android USB Host? You may ask. You need to have a USB OTG (On-The-Go) Cable, a USB host mode drivers must be loaded on your device; a version of android OS that supports USB Host mode(probably Android version 3.1 and above) ; a driver, especially for the devices that you are plugging in and of course an Android powered device. USB Host mode support was introduced in Android version 3.1, therefore if you have this version or newer versions in your device then you are good to go. Although most of the third party ROMs adds USB Host mode support to phones that have hardware support but may not necessarily have the right OS or driver support.
Most devices that have hardware support and the latest OS versions are likely to have prerequisite drivers to enable USB Host mode. For devices that don’t have, you can find these apps on Play Store. Nexus one, HTC Incredible, HTC Desire are some of the third party and instructions and drivers available on Play Store. USB Host mode (OTG) cable is another requirement for android USB Host mode support. In that case you will not be using a normal USB Cable.
This is because a standard USB cable is meant to act both as a USB “slave” and USB “Host”. A USB “Slave” is meant to allow you to copy music or photos from your PC into your phone and vice versa while USB “Host” on the other hand allows you to plug a USB into your tablet and copy files. There is need for a way in which it can tell when act as a host or slave at any given time. Therefore USB OTG cable tells your device when it should act as a host.
A USB OTG cable is just like a normal USB cable but it has one of the internal pins connected to ground at one end. This is to allow the device know that it should act as a host. This is done technically by shorting the pins 4 and 5 to Ground in an OTG cable. Unlike most phones that additionally have micro-USB sockets and a “full-size” USB dongle at the other end; USB OTG cable usually has male Micro-B plug at one end and a female USB-A (full size) plug at the other end to convert between different sized connectors.
USB OTG cables are usually found cheaply on online market places like eBay and Amazon. Some manufacturers go an extra mile to sell their own branded USB OTG along with their devices. Fair enough for the tech savvy folks; you can learn online how to build your own USB OTG cable from a standard USB cable.
Most common devices, especially those with Android OS, should recognize USB Host device when plugged in and know what to do with it. Normal USB memory sticks or cameras that have PPTP support or uses Mass storage are already built into the OS.
However other USB devices like Bluetooth, Wi-Fi or 3G dongle may not have pre-built driver in OS of the device they are connecting to. In that case you need to run USB Host diagnostics on your android device in order to ensure that you have all the necessary hardware and software support for USB Host mode. You can find USB Host diagnostics on Play Store.