@Eduardo-Marín The UART on the Omega has been occupied by the serial terminal. If you want to use UART on the Omega, there are three options. The easier way is to use a USB-to-serial adapter to read the information from the rfid module. The second way uses Arduino Dock's TX RX to receive the data from the RFID module and send the information to the Omega via I2C. The final way does not require either the USB-to-serial adapter or the Arduino dock, but it requires you to modify and re-compile the uboot as well as the firmware of the Omega to disable the serial terminal.