Although it is possible to connect a USB printer to an Android tablet or smartphone this is not something that we recommend or encourage you to do, as the USB connection is highly unreliable when printing from a mobile device.
On some devices the USB connection is resetting from time to time and another port is assigned to connection. This can cause the printing to no longer work and you will need to rescan for the printer (also an additional dialog box may appear asking you to allow the new connection).
Our recommendation is to use a LAN printer instead, since the connectivity is far more reliable and you also get to plug in a charger into the order taking device – which keeps it charged and prevents the device from going to sleep mode and causing connectivity issues.
However, if the situation calls that a USB thermal printer must be used, then please check the guidelines below.
In case of using a thermal printer with a USB connectivity, make sure the Android mobile device has two USB ports. One for charging the tablet and one to connect to the printer.
You can obtain good USB printing results only with tablets that have the charger socket separate from the USB socket, otherwise the device will not charge and print in the same time (USB splitters won’t work).
Also make sure the order-taking is running an Android version 4.4 or higher.
In addition, make sure the USB cable that connects to the printer cable with the mobile order taking device is USB OTG (On The Go) which allows the phone/tablet to power the connection, like in this example: http://www.mln.com.au/img/files/4468/usb-otg-cable1.jpg
To set up the printer, make sure the printer is set to USB mode by following these instructions https://www.youtube.com/watch?v=Mlxp1e0L0qk
The printed result should look like in this video: https://goo.gl/photos/1gsnCNGADsXtofS37
Important: watch both movies to the end.
Please restart the printer a few times, wait 20 seconds and then try to scan in the app. If the printer is identified in the order taking app, you should be to connect to it and print orders.