usb to rs232 communication app

Hi, I want to make android version of my PC (C#) code which connects to a OBD-II scanner circuit through USB to RS232 cable. when I connect the device to my android tablet its shows up as /dev/ttyUSB0. I can send and recieve data through “slick USB 2 serial” terminal app successfully. Having almost no knowledge of android development I would like to seek help from this forum. if anyone could help, it would be highly appreciated. I only need a kick start for which I need a simple app which has a button and a text box. when button is pressed a string “abcd” is sent and the received data should be displayed in the text box. I searched a lot but couldn’t get any easier guide. although I did find this app with source code: code[dot]google[dot]com/p/android-serialport-api/ but I dont really know how to proceed further....