How do I enable VOX (voice-activated) mode on the RT628?

Press the Menu button four times until the (⚙️) symbol and a blinking "1" appear on the LCD. Press the Up button (▲) to set VOX sensitivity to the highest level (3), then press PTT to confirm. The (⚡) symbol will display continuously when VOX is active. Note that VOX operation is not recommended in loud or windy environments.