How-to View Security Cameras from Multiple DVRs on One Screen

Please let me know how to connect to two or three DVRs so that I can view the security cameras on all of them on a single screen. How do I download the CMS software to do this?

Also, how do I setup port forwarding for each DVR?

Above is a questions that CCTV Camera Pros technical support received today. Here is the information that we provided to the customer.

Thank you for contacting CCTV Camera Pros. Our most popular CCTV DVR, iDVR-PRO, supports viewing and managing multiple DVRs using the CMS software that is included. You can find 4, 8, and 16 channel iDVR-PRO DVRs on this page.
https://www.cctvcamerapros.com/HD-Security-Camera-DVRs-s/972.htm

The latest iDVR-PRO surveillance DVRs now support analog CCTV cameras (standard definition) as well as HD security cameras (AHD 720p and 1080p). You can find HD cameras here. All of the cameras on that page work with iDVR-PRO.
https://www.cctvcamerapros.com/AHD-HD-CCTV-Cameras-s/919.htm

This video will show you how multiple DVRs can be connected to using the CMS software. Using the CMS software, you may configure custom security camera views consisting of cameras from multiple DVRs / locations.
https://www.cctvcamerapros.com/Remote-View-CCTV-Security-Cameras-s/906.htm

The below image shows the iDVR-PRO CMS software for Windows connected to two DVRs and viewing 3 cameras from each DVR on one screen.

Here is a link to the setup instructions.
https://www.cctvcamerapros.com/Monitor-Multiple-CCTV-DVR-Locations-s/907.htm

The CMS software can be downloaded here. iDVR-PRO CMS software is available for Mac and Windows PCs. The Windows version supports unlimited DVRs. The Mac software is limited to 2 DVRs.
https://www.cctvcamerapros.com/CCTV-DVR-MAC-Viewer-s/403.htm#software

If multiple DVRs are on the same network, you just have to configure each DVR to use different ports for the http and rtsp video streams. Then, forward the ports that you configured. It is very simple. If you need help, our tech support team can login to your network to help configure this for you.

Please let me know if you have additional questions.