ByAl Gordon
Columnist

Among the hot items in wireless technologies are "MIMO" and "Bluetooth," which raise a number of questions. Notably: What are they? And why do we need them?

MIMO is a new wireless networking technology. The name sounds like the title of a Disney-Pixar animated character, but it's an acronym for "multiple input, multiple output." As geekspeak goes, that's relatively self-explanatory. Instead of a single wireless radio to send and receive like current devices, MIMO units use multiple radio signals. The result is longer range and the ability to carry more data at once.

Bluetooth, on the other hand, is a wireless technology designed for use over short distances (10 meters, which is a little less than 30 feet). It is one of the few technologies ever given an interesting name. Danish King Harald Bluetooth is famous figure in Scandinavia, and the Scandinavian electronics companies that invented the standard decided to honor him.

More interesting than the "what" of these technologies, though, is the "why." People tend to think of the tech world as evolving in some kind of mathematically precise fashion. What more often happens is that someone invents or conceives of a new technology and then either tries to figure out a practical use for it (Bluetooth) or win acceptance for it as an industry standard (MIMO).

Bluetooth came very close to being a high-tech version of the answer to a question no one was asking.

Part of the original conception was that Bluetooth would be a wireless replacement for connector cables for such purposes as hooking up peripherals. You might connect, for example, your laptop to a printer or sync your personal digital assistant (PDA) to your PC. While once upon a time wired connections were difficult -- remember those old printer cables with the thumb screws that required you to shut down your PC? -- the advent of plug-and-play connections make hooking up peripherals easy.

Setting up a Bluetooth connection, on the other hand, is not easy. Bluetooth requires add-on hardware on most Windows PCs and Microsoft only recently added Bluetooth support in Windows. Setup, thus, can be a pain. I have a couple of Bluetooth PDAs, for instance, for which connections are, say we say, problematic. (Many Macs have built-in Bluetooth and thus handle it better than Windows PCs.)

What eventually made Bluetooth successful is that cell phone makers were among its original developers and they implemented it successfully. Wireless headsets make sense and they work. You really do just push the "on" button and they connect. A little credit also goes to Honda, which as far as I know, was the first automaker to use Bluetooth as a built-in hands-free car phone device -- another logical choice that works well.

MIMO, meanwhile, has the reverse problem -- it has worked right out of the box. But will it survive long-term? In an early column here, I discussed the problem of wireless "traffic congestion" -- so many people are setting up wireless networks that they are interfering with each other. MIMO devices offer greater signal strength to permit longer range transmissions and more data to be sent at once. The former helps overcome interference issues; the latter is to enable such data-intensive uses as transmitting video.

I tested Linksys's WRT54GX wireless router and WPC54GX notebook card and saw substantially improved coverage in my home. I no longer needed signal boosters or repeaters -- additional radios, in other words -- to maintain signal strength throughout. With an all-MIMO system, performance was clearly improved, but I also saw definite gains in range and signal strength when I used older wireless units with the new router.

Eventually there will be a new wireless standard, with the catchy name "802.11n." The people who make MIMO circuitry are lobbying for it to be the basis of the standard but rival groups propose other technologies. A decision is thought to be about two years away.

Linksys scores points with me for branding its MIMO as "SRX" ("Speed and Range eXpansion"), with no implication of potential "n" compatibility. The company sells the technology as something that works now, without any marking promises it may not be able to keep. Makes sense to me.

NOTE: In an earlier column on satellite radio, I recommended XM on the basis of its subscription fee being $3 cheaper per month than rival Sirius's. XM recently upped its price to the same $13 per month as Sirius. So disregard my previous recommendation; the choice now is strictly pick 'em.

Al Gordon is a Massachusetts-based media and political consultant who also writes about technology. You can read more of his articles at www.tnpcnewsletter.com/al and e-mail him at eagle@algordon.com.

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