This paper shows the design and construction of a two factor authentication security system, with a

dial-up system. It is based on what the user knows (password) and what he has (smart card). The

system consists of a microcontroller 89S52 which sends a signal to the multiplexers on insertion of

the smart card in the card slot. consist The multiplexers of ICS which prompts for a display of the

identity of the card user in the seven segment display. The seven segments display the status of the

card. On validation of the card, the seven segments display a welcome note to the user and prompts

for a pin code. The pin code is being keyed in from the key pad. If confirmed by the program written

into the microcontroller access will be granted, otherwise no access, giving the user two more

chances to insert the correct smartcard or pin code to it, before final denial of access which displays

“Access Denied” on the Seven Segment Display and triggers an alarm and a dial-up system

which will call a pre-programmed cell phone number. When access is granted, the card sends a

5volt signal to the microcontroller which triggers relay, resulting in the opening of the door.