Card Reader

A card reader is a data input device that reads data from a card-shaped storage medium. Historically, paper or cardboard punched cards were used throughout the first several decades of the computer industry to store information and write programs for computer system, and these were read by punched card readers. More modern card readers are electronic devices that use plastic cards imprinted with barcodes, magnetic strips, computer chips or other storage medium.

It is the types of biometric product. There are two types of Card reader:

First one is Proximity Card & Second one is Mififair. Both are useful for card reading, sums sending or many uses .MNC Companies are uses both biometric product for attendance purpose.

Proximity Cards

Proximity card is a generic name for contactless integrated circuit devices used for security access or payment systems. The standard can refer to the older 125 kHz devices or the newer 13.56 MHz contactless RFID cards, most commonly known as contactless smartcards. It is look like ATM card or PAN cards. It is very best way to recognize to the member & given signal to the People those are use cards.

The Wigand effect was used in early access cards. This method was abandoned in favor of other technologies. Card readers are still referred to as "Wigand output readers" but no longer use the Wigand effect. The new technologies retained the Wigand upstream data so that the new readers were compatible with old systems. A proximity reader radiates a 1" to 20" electrical field around itself. A common proximity format is 26-bit Wigand. This format uses a facility code, sometimes also called a site code. The facility code is a unique number common to all of the cards in a particular set. The idea is that an organization will have their own facility code and a set of numbered cards incrementing from 1. Another organization has a different facility code and their card set also increments from 1. Thus different organizations can have card sets with the same card numbers but since the facility codes differ, the cards only work at one organization. This idea worked fine for a while but there is no governing body controlling card numbers, and different manufacturers can supply cards with identical facility codes and identical card numbers to different organizations. Thus there is a problem of duplicate cards. To counteract this problem some manufacturers have created formats beyond 26-bit Wigand that they control and issue to organizations.

Lots of companies use proximity cards to control physical access. An employee holds their card within a few inches of the reader; the reader receives a unique id from the card and transmits it to some central computer that tells it whether or not to open the door. This is rather magical, considering that the tag is credit card-thin and contains no battery. The trick is the same as for RFID tags. The reader constantly transmits a rather strong carrier; the tag derives its power and clock from this carrier, kind of like a crystal radio. The tag changes how much carrier it reflects back at the reader—loosely, it makes the circuit across its antenna more like a short or more like an open—to transmit its code. The reader and the tag both have antenna coils tuned to the carrier frequency; they work like a loosely-coupled resonant transformer.

The Many Faces of the Proximity Card

It seems like everything eventually changes. Identification cards are no exception to the rule. The identification process has changed as well as the population has exploded and the ability to identify everyone has gotten harder and harder.