This month's Java Developer column, called "An introduction to the Java Ring," describes the history of Dallas Semiconductor's Java Ring devices and provides a background on the theory behind them. This iButtons article (along with a forthcoming article on serial device support using javax.comm) provides the information you need to develop application solutions using Java Card. The javax.comm API is used by the host software to communicate with the reader, which in turn communicates with the card or ring. For more information on readers and terminals, see the first article in this smart card series.

Java Ring
This article will get you started on the road to understanding how to develop applications for Java Card. You should be able to get a Java iButton ring and a reader -- smart cards need something to plug into -- for 0.00. Take a look at the Resources section for more information on what you need and how and where to order rings and readers. The software is available over the Internet.
We're finally ready to solve a real-world problem with Java Card.
Using the information in this article, as well as that material gleaned from the other articles in this smart card series, you will be able to interface a device to a browser and have the data bounce off of the ring or smart card instead of the hard disk. Why would you want to do this?
How many times a day do you have to give someone your business card information verbally? Worse yet, how much time do you spend collecting business cards to scan into your computer for access later? I provide business card/personal information so often that I will happily pay for any technology that provides a solution. It's rather odd that phone companies don't provide a simple, automatic option for transmitting this kind of information -- commonly referred to as profiling information -- over the phone.
There are some standards in motion to provide this service from any Web browser. Recently, browsers have started to add sections that contain common business card information. At the current time, however, no browsers support a business card that is also "smart."
The standard being proposed for personal information is OPS (Open Profiling Standard), and a proposed standard for EDI (electronic data interchange) on extranets is called "ICE." The standards themselves are quite large and we can't possibly cover them in this short article. We can, however, show you some of the core components that could be used to build such a profiling information delivery system.
Winzip may be required. You will see several directories. Start by reading the README file. To run the demos you will need to connect a reader to your computer. BusinessCard.java is a listing of the Java Card
applet included here for convenience http://www.ibutton.com/devkit