Door security is often the first line of defence in any property. A simple door-phone will give the occupier a means of communication without opening the door, or by using a video door-phone, add a picture to accompany the visitor's voice. For larger commercial properties, a coded access system using magnetic swipe cards or just a higher capacity door-phone system may be required. There are various options on these types of door entry systems and each installation must have its own unique planning survey.