When using a DVR for security surveillance purposes there is a dvr protocol that has to be followed. When the dvr is connected to any other type of equipment the other instrument will be the one instructing the dvr what to do. For example, a camera will send the information to the dvr informing it to record and any other requirements that need to be done. Partnering a camera along with a dvr is an excellent way to get the surveillance that you need without spending alot of money and having to install a bunch of different things to your home.