DIGITAL DOOR LOCK HAVING DETACHABLE FUNCTION EXTENSION MODULE

Disclosed is a digital door lock having a detachable function extension module. An inputting unit receives a user information including at least one of a common information used in common by a plurality of users and a personalized information inherent to each user. A locking function unit converts a door to a locked state or an unlocked state. A control unit serves to compare again the inputted user information to an authentication information when the inputted user information is inconsistent with the authentication information and to block the operation of the inputting unit and then convert the inputting unit to a forced block mode if the number of inconsistency reaches a decision number. In particular, the digital door lock may have a function extension module mounted therein which implements a function of calculating the degree of similarity by comparing the inputted user information to the authentication information and a function of reducing a block time period in which the forced block mode is maintained if the degree of similarity is greater or equal to a predetermined value when the door or the inputting unit is converted to the forced block mode.