# Working with NVRs

Navigation: Working with Nx Witness > Device Management (Cameras, Encoders and I/O Modules) > # Working with NVRs |

Nx Witness can work with a wide number of n etwork video recorders (NVRs), however there are some special requirements:

•NVR requires a specific Bridge License to work (however a regular license will work as well). Each Bridge License allows viewing one channel from NVR.

•NVR cannot be detected automatically and must be added manually. See "Adding Devices Manually".

•Cameras should be connected to NVR and properly configured to display in Nx Witness.

After an NVR is configured and added, its channels become visible and it is possible to navigate through its live and archive streams. Some restrictions apply:

•NVRs do not support asynchronous playback, so the SYNC button on the Timeline has no effect.

•Only three simultaneous connections per channel are supported for archive playback. This means only three Nx Witness Client applications may request video from a certain channel. If an additional client tries to view archive from this channel, it will not be accessible.