Two-way audio enables you to receive and transmit audio through the IP camera. Reolink cameras that support Two-way audio have a built-in speaker and microphone, you could talk through the camera via your Reolink App/Client when you are far away from home.
Applies to: E1, E Series E320, E1 pro, E1 Zoom, E Series E340, E1 Outdoor Series, Reolink Lumus, RLC-511WA, RLC-523WA, RLC-840WA, W337, RLC-843WA, W437, RLC-540A, P327, RLC-811A, P430, RLC-812A, RLC-823 Series, RLC-824A, RLC-81MA, P330M, RLC-81PA, P330P, RLC-830A, P830, RLC-833A, P434, RLC-843A, P437, RLC-840A, P337, RLC-1240A, P347, RLC-1212A, P341, RLC-1224A, P345, B1200, P341C, D1200, P345C, FE-P, Fisheye Series P520, FE-W, Fisheye Series W520, CX410, ColorX Series P320X, CX410W, ColorX Series W320X, CX810, ColorX Series P330X, CX820, ColorX Series P335X, Reolink Duo series, Reolink TrackMix series, Reolink Video Doorbell series and all Reolink battery-powered cameras.
You could follow the articles below to enable Two-way Audio for your Reolink Cameras:
Enable Two-Way Audio via Reolink App
Enable Two-way Audio via Reolink Client (New Client)
Note: If you connect the cameras (except for battery-powered cameras) that support two-way audio to the NVR, the Two-way audio function can not be used between the camera and NVR since Reolink NVR does not have a microphone and doesn't support the two-way audio feature. But RLN36 NVR supports the two-way audio feature, so you can connect a microphone and speaker to it or use the Reolink App/Client to use the two-way audio feature for the RLN36 NVR.