Magnetic Card Reader

MAGNETIC CARD READER

What is it?

A magnetic card reader contains either a magnetic object embedded within the card or a magnetic stripe on the exterior of the card. According to existing standards, a magnetic card stores information in three separate tracks. All three tracks possess different bit densities and encoded character sets. The average bit density of the first track is 210 bits per inch (bpi). A 64-bit character dataset is used to store information in track 1. The characters are made up of six data bits and an odd parity bit. The encoding format grants the least-significant bit to come first and the parity bit, last. So, track one can hold around 79 characters.

What is it for?

This electronic device is designed to read stored information from a magnetic card by means of swiping the card through a slot in the reading device or holding the card next to a magnetic card reader.

What does it look like?

It is a rectangular plastic object that looks like a credit/debit card

What is the technology behind it?

"Two-Frequency, Coherent Phase Recording" is used for encoding magnetic cards. It is also called as F/2F sampling-encoding. By using combined data and clock bits self-clocking is achieved. The reader also contains an oscillator section which is used to provide the clocks for the recovery section and for the enable/disable timers. The enable/disable counters provide initialization for the recovery section. The recovery section locks onto the data rate and recovers the individual data bits from the data stream.

The magnetic card reader is a microcontroller-based device and has been programmed for a specific application. That program simply reads the card in a forward direction in a simple data format or it can be complex enough to read the card in any direction with a corresponding encoding format.

Sources:

http://www.epos-store.co.uk/images/powermag.jpg

http://www.tech-faq.com/magnetic-card-reader.shtml