RX/TX pin not blinking

[Patouf]

Hi, I just wanted to know if it is normal that my RX/TX leds (those between the two USB ports) are not bliking when I use Serial Communication?

[hiduino]

Those two are not used for serial communications.  They are connected to digital pins 72 and 73.

The other two Tx/Rx LEDs between the Power Jack and Programming port are used for serial communications on the USB Programming port via the ATmega16U2 chip.

[Patouf]

Thanks for your answer But what are the tx/rx led for if they do not blink when I use the serial (not the one on usb)?