Call the other party, the red light will indicate. If there is a transceiver frequency point along the channel.
Press PTT and speak into the microphone to indicate, if there is a signal, the green light will be on, and when you release it to receive, it will beep and turn on the speaker.
This function is set to high power by default in the factory. You can choose whether the channel works at high power or low power by setting the "High/Low" option of "Transmit Power" in the frequency writing software.