When you need to restrict or control who has access to a certain area then the use of an Access Control System(ACS) is essential. There can be different types of Access Controls Systems, from the easiest and simplest stand-alone door control system to the more complex using a PC and LAN (local area network). This ACS restricts unauthorised entry to a building or room by electronic means and is not to be confused with Physical Access Control (PAC) which is where a human guard will give or prevent access to a certain area.
The swipe card is an older method of ACS, but is still in common use today. The card is now being replaced by proximity cards or key fobs to allow access to areas by a person`s individually coded card or fob that is unique to them. This useful system is great because access can be stoppped at anytime by cancelling the card or fob e.g. the employee has left employement, but still has a card or has had the card lost or stolen.
They are hard to copy because you would need to have a reasonable knowledge of Radio Technology, Microchips and the software used, making it almost impossible to fake.
This as it sounds allows a person to key in a certain code of numbers that can be generic in some cases or specific to them on some keypads to allow authorised access. This ACS option is always recommended for only small groups of employees and there is a security risk that the code could be shared around.
The authorised user can just pass a fob near the reader to be allowed access. Again as before with the keypad, the fob can be easily shared around, but you could increase the security aspect by using the fob and keypad together for that little bit extra Access Control.