Disconnecting Arduino from the USB and trying to communicate over TX/RX

I am trying to have the arduino continuously send serial data over TX/RX pins. Once I upload my program onto Arduino using the USB, then unplug the USB, will Arduino automatically start transmitting the serial data over its TX/RX pins (assuming its supplied extermal power)?

Thanks.

Do you have the Arduino Uno board ? The RX (pin 0) and TX (pin 1) are always connected to the usb-serial. If you connect something else to pin 0 and pin 1, the signals of the usb-serial are overriden, but they are still connected. That is regardless if the Arduino board is powered with the usb plug or not. So you can keep on using the usb to power the Arduino.

nonomus: I am trying to have the arduino continuously send serial data over TX/RX pins. Once I upload my program onto Arduino using the USB, then unplug the USB, will Arduino automatically start transmitting the serial data over its TX/RX pins (assuming its supplied extermal power)? Thanks.

I would think it would.

Yes it will.