USB OTG technology on Android. Capabilities and Applications

USB OTG ("On-The-Go" - On the Go) is an extension of the "USB 2.0" specification that allows you to connect peripheral devices without using a computer. An alternative name for the technology is USB-host. Using a USB OTG cable, you can connect a flash drive, hard drive, camera, mouse, keyboard, joystick, printer, etc. directly to an Android smartphone or tablet, provided that the gadget supports this technology both at the software and hardware level. A typical USB OTG cable is shown in the photo below.

The USB OTG standard uses a "master/slave" architecture. That is, the Android device performs the function of the master, and the peripheral device functions as the slave. The master device is a power supply device, and the slave device is a current consumer.

When connecting via the USB OTG standard, the roles of the master and slave devices are determined by the presence or absence of a jumper between the 4th and 5th pins in the connector of the connecting cable.

There may be a case of partial support of “USB-host” by an Android device (most often observed in smartphones), in which the device can control peripherals without providing it with energy. In this case, additional devices are connected via an active USB hub that has its own power supply. If you have an interest in electronics, you can solder an OTG cable with active power yourself. There are many schemes available on the Internet.

Some examples of using a USB OTG cable

Connecting a flash drive

Everything is simple here, connect the cable with a “Micro USB” plug to the Android device, and insert a flash drive into the socket at the other end. The message "Preparing USB storage" will appear in the notification area for a second. All! Now you can open any file manager and manage the contents of the flash drive. The name may be different in different conductors. In the file manager "ES Explorer" the flash drive is designated as "usb_storage".

After finishing work, it is better to safely disconnect the flash drive to avoid spontaneous rebooting of the device. Go to Settings > Storage, scroll to the bottom and click Unmount USB.

After a few seconds, a message will appear in the notification area informing you that it is safe to remove the flash drive.

Connecting a computer mouse

Low-level peripherals such as mice and keyboards are connected immediately after they are connected, without additional installation.

Use as on a computer: double click to launch the application, single click to select it.

Connecting a printer

The following Android applications allow you to connect the printer to your gadget via a USB OTG cable.

Unfortunately, they all support a limited number of printers (the most common models).

Using the PrintHand application

Connect the printer to your Android device. Open the application, scroll down the menu on the left and click on the "Add Printer Assistant" button.

In the second step, select the “Printer connected to Android device via USB” option.

A message will appear in the notification area, click on it. This will open the Android Printing Service Settings. Turn it on.

After a short wait, you will see the installed print service for the "PrintHand" application.

And if your printer is supported, the installed printer.