Now that virtually every laptop on the planet has an IrDA interface on it, and Bluetooth is getting strong support from many of the world's leading technology companies, the question arises about which is best for use in Windows XP Professional. Bluetooth even has its own globally focused special interest group (http://www.bluetooth.org) in addition to a public information site at http://www.bluetooth.com. The IrDA user group has been around quite a bit longer, and has chronicled its history at http://www.irda.org. The fact that IrDA has such a successful design-in record is exemplified in the strong showing it continues to receive in many products over and above the laptops it has become pervasive in.
Although at first there appears to be a marked difference between each technology, they are in fact very similar to one another. The intent of this article is to define which given applications of Windows XP Professional are best suited for IrDA and which are best suited for Bluetooth. Increasingly, peripheral companies are starting to look at each as part of a broader short-range wireless product strategy.
Getting Familiar with IrDA
Starting out as a point-to-point protocol for transferring at speeds that approximate 4MBps, IrDA can theoretically run as fast as 16MBps, but slower speeds are much more common. The short-range of less than one meter is what makes IrDA ideal for laptops. When the standards organizations met to define the details of the IrDA interface, they actually created three separate standards. The first is the IrDA-Data standard, which is most often referred to, especially in conversations that include references to Bluetooth. The other two IrDA standards include IrDA-Control and Alr, both of which are not referred to because the IrDA data standard is the most prevalently used.
The fact that IrDA pioneers the use of wireless interfaces on mobile devices including laptops has driven it to more than 150 million units worldwide currently installed. At the core of this technology is a cone-shaped transmission area that transmits in a point-to-point communications approach. Unlike HomeRF, which is in fact a directionless protocol that broadcasts outbound messages through a concentric area, IrDA relies on recognition of a second point before broadcasting or sending a message. This makes IrDA more secure than other wireless technologies used in small offices and homes today. The drawback with IrDA is distance, of course, which is a one-meter limit.