The 'Other' Wireless Technology is Alive and Kicking

With all the buzz surrounding WiFi (802.11b), WiFi's alphabet-soup cousins (802.11a/g/h), Bluetooth, and lesser-known wireless RF communications technologies, it's easy to lose sight of a non-RF wireless technology near and dear to everyone—infrared. Although never widely accepted as a notebook or laptop computer port (I bet your laptop is infrared-enabled), reports of the demise of infrared for communications applications are greatly exaggerated.

Before offering my opinion as to why IR communications will flourish and co-exist with Bluetooth as a cable-replacement technology, let me clarify a couple of points. By IR communications, I mean two-way communications between units. Your TV remote, while IR-enabled, is not a communications device—it is an inexpensive and relatively low-tech (utilizing a 40 kHz modulated IR beam) control device. This indispensable couch-potato tool—along with its cloned stereo, MP3, and camera controllers—make up a huge market that will continue to expand rapidly as equipment for personal-entertainment and home-entertainment centers multiplies.

'Real' IR-communications devices comply with the protocols and specifications of the Infrared Data Association (IrDA). IrDA's mission is to, "Establish and promote an infrared standard that provides convenient cordless connectivity and fosters application interoperability over a broad range of platforms and devices." IrDA-compatible devices are bi-directional and point-to-point, operating at rates typically ranging from 115 kbps to 4 Mbps, line-of-sight (within a 30-degree reception cone), and over a 1m range (typically, IrDA-compatible devices can operate to 2m and some also operate in a low-power, reduced-range mode). Since current Bluetooth-enabled devices are point-to-multipoint, can operate in piconets, and are specified to operate at 1 Mbps (720 kbps effective) over a 10m range, you might ask why someone would want to use IR instead of Bluetooth. The three-part answer is: cost—security—interference.

IR-enabled communications is presently less expensive than Bluetooth, about half the cost, and will probably stay that way. This allows manufacturers to develop and use IR technology for a broader range of consumer applications. Being short-range and line-of-sight, IR technology is inherently more secure from unauthorized eavesdropping and interference than the omnidirectional, longer-range, 2.4 GHz Bluetooth. And, speaking of interference, similar to devices operating in the 900 MHz spectrum interfering with other like-frequency devices, Bluetooth is more prone to interference from other Bluetooth devices, cell phones, microwave ovens, and other equipment operating at 2.4 GHz. Finally, unlike RF technologies, IrDA is unregulated, simplifying the technology's development and adoption.

I think IR communication, using the IrDA protocols, will do well for a few reasons. First, the Infrared Data Association, originally technology-driven, is now putting more emphasis on IR communications applications. For example, the adoption of IrDA technology was slowed by a lack of standardization at the upper protocol layers. Bluetooth has a similar problem with its multiple profiles, which control Bluetooth device behavior. Lack of IrDA protocol standardization was a major reason for the non-use of a notebook's IrDA port—peripheral manufacturers had different ideas of what the protocols should be for their particular devices. The Association is working to overcome these types of problems. Second, IrDA devices are very low power and thus well suited for personal, portable applications using inexpensive batteries. Finally, IrDA devices are ideal for 'ad hoc' communications, where you don't have a pre-defined communications infrastructure. Again, this fits well with the concept of personal device communications.

Look for growth in IrDA-appliance use in the following areas: financial and other point-of-sale (POS) number/keyword sensitive transactions (e-wallet), intra-room Internet access outside the home (hotels and offices), and, yet again, cable-free connectivity between your PC and peripheral devices. I believe that e-wallet applications are particularly interesting, since their operation eliminates the possibility of prying eyes looking at credit card numbers and other information of value to identity thieves. For more information, check out IrDA's overview of the Infrared Financial Messaging (IrFM) specification.

Jim Lipman is a consultant providing marketing, writing, and other electronics industry services, specializing in EDA tools and ASIC/SoC design methodologies. His job experience includes chip-design R&D, marketing, marcom, technical editing, and on-line publishing of technical content for engineers.