In order to possess security in the most uncertain daily life, door access system has an important role to play. There are many situations where it is used to save information - important to a person, a project, a house, a company even. This is used somewhere to save things which are valuable to different levels of people.

A PABX telephone system is programmed in such a way so that it greets each caller with an automated message before the call goes through to the assigned line. PABX machines are now being modernized in that now they can be controlled by a computer system which tracks all incoming and outgoing calls of the clients. Hence, basically, the PABX is an internal telephonic network, which covers the whole world.

Home burglaries -- a threat to the world -- a threat to the social security system -- the issue is addressed by using alarm system in some places where important valuables like money, antique pieces, and above all human lives needs to be secured. In the beginning of burglar alarm systems, closed circuit cameras and video recorders are used as security measure.