Use of smart cards is increasing, but they are not yet considered commonplace in the United States. It is also possible to combine more than one technology on a single multiple-technology card. In an upgrade, this approach can make it possible to continue to use existing cards. In all cases, the key is to select the cards and readers that meet the specific needs of the application. Another electronic access control option is the use of keypads.
Some applications involve keypads only, while other systems employ both cards and keypads.
Sometimes these units are used as a simple measure in a first line of security, where additional and presumably more effective methods are also used elsewhere in the security program. For example, a keypad might be used to open a motorized gate to an employee-only parking lot or area, where an additional key or card reader is required to gain access to the facility. The problem with most keypad-only systems is that an observer can steal the code and gain entry simply by watching someone using the proper access code. At least one manufacturer produces a keypad system which rearranges the numerals on the keypad each time the unit is used as a means to deter the would-be code stealer. Combination card and keypad systems are common in applications where a higher level of security is mandated, such as airports.