Re: What are the differences between bar codes and magnetic strips???

Hello, Sarah. Well, a major difference between bar codes and magnetic strips is 
that the information is stored in a bar code optically, as a series of 
rectangular black or white rectangular shapes, so you can see the bar code 
visually (see the bar code image below), while magnetic strips store the 
information magnetically, as a series of North pole-magnetized (N) and South 
pole magnetized (S) regions. So, you cannot see the magnetic strip's code 
visually.(see the magnetic stripe image at the bottom of this page). The fact 
that the magnetic strip's information cannot be obtained just by looking at the 
magnetic strip is why confidential information like your credit card number on 
your credit card is typically stored as a magnetic strip rather than as an 
optical bar code.

Here is a web site that explains bar codes and how they work:

How UPC Bar Codes Work

For magnetic strips or stripes, there are three tracks - tracks 1, 2, and 3, 
each of which are intended to do different things. Track 2 is generally the 
track that is actually used most often. Here are three web pages
that explain magnetic strips and how they work: 

"How Stuff Works: How Does a Magnetic Stripe Work?"

"Card-O-Rama: Magnetic Stripe Technology and Beyond"

Magnetic Stripe Technology