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, 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.