Sorry I can't even answer what system the cameras are. Where do I check. I'm so clueless about all of this.
Some of the cameras are recording all the time, some are motion detect. Those of course, have big gaps. I have a camera in the room where the alarm has to be shut off, and thought I would see someone before they could do that. I have looked on the DVD for things that have been broken. It will show when the item is OK, then skips ahead to where the item is broken. You can never see what actually happened, which would have been a good sized motion.
I read in another forum, that someone else was having this problem a couple of years ago, and wanted to know how the system could be bypassed. It sounds insane, but things are taken from the house, brought back, so subtle you don't find out right away. Some things are brought in that aren't mine; other things are badly damaged. It is a drive you crazy ordeal. The couple who wrote the original forum article said it sounds insane, but is totally true - it is not our imaginations!