Arecont Vision Day/Night cameras (models ending with -DN) are compatible with IR illumination sources. -DN model cameras include an IR cut filter which allows for IR illumination to be filtered out during day operation and then exposed to the sensor during night operation. Without IR illumination, a -DN model camera will be subject to the existing illumination in the area. If no light (visible or invisible) is present, the camera will not be able to pick up an image at night.
Arecont Vision MegaView camera models ending in -IR have an onboard IR illuminator which will activate when the camera enters night mode. If this IR illumination is not visible, ensure that appropriate power is being supplied on the power connector for the IR illuminator.