Just connect a USB serial adapter into USB OTG port of your Android device, start this app and connect to it using any Telnet client like:
* JuiceSSH using the same Android device (connect to localhost)
* Telnet client on a computer on the same network (connect over Wi-Fi)

This method allows to use all console features like colors and special keys. So you can easily control/install something like network devices with serial port using only your Android device. Also, you can use it as remote console transmitter.

This app uses usb-serial-for-android library by mik3y and supports USB to serial converter chips:
* FTDI FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
* Prolific PL2303
* Silabs CP2102 and all other CP210x
* Qinheng CH340, CH341A

devices implementing the CDC/ACM protocol like:
* Arduino using ATmega32U4
* Digispark using V-USB software USB
* BBC micro:bit using ARM mbed DAPLink firmware