QCam Link app uses a data stream that will connect to your DVR / NVR/ IP Cam via 3G/4G or WiFi. When using 3G/4G, the video from your DVR will likely be considered "downloads" by your mobile device service provider and will contribute to any download limit your mobile device data plan may have. If you exceed any plan limits you may incur additional usage charges. Consult with your mobile service provider regarding the use of a video streaming app and how it may affect your plan.