If you live in a big building and huge dogs roam the hallways and block your access to the frontdoor, you have to invest in one of these systems. It allows you to communicate with salespeople or Jehova witnesses stuck at your front door at any time of the day and night. This video interphone allows you to see (on a colour screen) who is buzzing your doorbell. From either a fixed monitor or a wireless handset you can fob them off without any effort. On sale from December 1st onwards, but no price info yet.