D-Link DCS-942L Faq page 25

Enable Video Motion: Select this box to enable the motion detection feature of your camera.
If this option is selected, enter a level of sensitivity in the Sensitivity field adjacent to the
video window. You also need to select the area of the video that you want to include or
exclude for motion detection. You can choose to Draw motion area, whereby the selected
area will be included for motion detection, or Erase motion area, whereby the selected area
will be excluded from motion detection. To select an area, click and drag your mouse over
the required area. Click Clear to delete all selections from the video window.
Enable PIR: When this option is selected, the camera will use PIR (Passive InfraRed) motion
detection. If this option is enabled, select a PIR Sensitivity from the drop-down menu.
Step 8: Click the Save Settings button to save the new configuration.