You may refer to the following steps to enable two-way audio function for Reolink cameras via Reolink Client (Windows).
Note: Please make sure that the microphone/speaker could work on your PC before using the two-way audio.
Step 1. Launch Reolink Client and log in to the camera, then go to Device Settings -> Record Encode page to enable the audio.
Step 2. Turn on the volume at the bottom of the Live View page, then click on the icon. When the icon turns blue , the 2-way audio function is enabled and you can talk now. To turn the microphone off, please tap on the icon again.