The video feed can be routed to your television and left up in the "picture in picture" small window.
I know several cops in the Dallas area who have upgraded their home alarms with camera systems. When the cops start beefing up their home security, it's definitely time to worry.
The Dallas cops I’ve talked to who did that cited liability and internal affairs reasons for doing that. Seems that if you get the whole affair on video when you have to open fire on an intruder and you did it by the book, it takes a *lot* less time for IA to clear you.
Home video surveillance systems are cheap enough now. You can put a decent one together for under $300 now or you can spend $500 and get a ridiculous number of cameras.