For this article, I will provide some information about the four-camera DVR security systems I've installed at both my parents' residence and my home. I'm not going into details of where each picture is, save that both locations always are recording, able to run during a power outage, can easily provide playback, and are remotely accessible. In the case of the DVR for my house and office (which is an "IP Camera", which will be covered in a separate article), I am able to view live content from my smartphone.
Several months ago, Google bought out a camera manufacturer, which they likely will be promoting later. From what I previewed, despite the ability to save video to your Google Drive, each camera was a separate system, and more expensive than what is available elsewhere. I've taken the route of an inexpensive DVR that has enough functionality, able to use common exterior cameras with infrared capability (meaning no additional lighting for grayscale video at night).
The power requirements for the DVRs and cameras (I will say that the unit my parents have doesn't have the smartphone capabilities mine does, nor is it needed there, although brand is the same) is 12-volts DC, which as you know has a common ring for the other equipment I have. There are common terabyte drives on the DVRs, able to record full-time for over a month with four cameras. Playback is easy to do, by just selecting the segment you want to view, either locally or remote over the Internet (access is password-protected, and generally only older Internet Explorer browsers can be used if they do not have the DVR software installed).
If you have an area beyond 20 feet that needs to covered at night, I've also set up additional IR assemblies to add night illumination. The IR LEDs do not give visible light, someone within 25 feet only sees red dots on the camera or additional lamps. A sensor turns on the IR LEDs in low-lighting situations automatically.
Here are a few pictures, exterior camera (and additional IR LED lamp), a dome camera (the comparable IR LED unit looks the same as the camera), and a wall plate close to one of the DVRs, carrying power to the cameras, an Ethernet link back to the DSL modem, and BNC connections for each of the four cameras. In a later article I'll show the cables commonly used and more details.