Troubleshooting Q&A - March 18, 2004
Bluetooth vs. Wi-Fi Technology
Keeping current with the multitude of home networking technologies can be quite a challenge. It's all too easy to get lost in the endless avalanche of new acronyms and technologies. This week's Q&A compares and contrasts a couple of commonly confused technologies — Bluetooth and Wi-Fi.
By Ron Pacchiano
Q. For the last 15 or so years I have been a loyal Windows user. As with many relationships, this one has not been without its occasional problems. Over the years I’ve lost count of how many times Windows caused a GPF or simply crashed on me. Two weeks ago I was right in the middle of one of the biggest presentations of my career when Windows crashed. It was a nightmare. Worst yet, I couldn’t even get back into the system. Thay was the final straw.
The very next day I went out and purchased my first Apple computer — a PowerBook G4 with a 12.1" display (Model # M9007LL/A). It’s really cool looking and everything seems to be working pretty well. It’s been a few weeks, and I’ve been very happy with it except for one thing that I hope you can assist me with.
Now this could just be my unfamiliarity with the Mac OS, but for some reason I can’t seem to get the system online. It looks like the MAC’s Bluetooth wireless adapter is not communicating with my D-Link DI-614+ wireless router. I’ve tried a number of things to get around this problem, like disabling WEP and verifying that DHCP has been enabled, but it hasn’t helped.
I know my Internet connection and router are functioning properly because my two Windows machines can get online just fine. I’ve tried calling tech support a few times, but so far I haven’t been able to get through to anyone. Is there anything you can tell me that might help rectify this situation? Thanks!
A. Hopefully, you’ve gotten through to tech support by now, but if you haven’t, I can tell you without question what your problem is. Simply put, I think you’re under the impression that your Bluetooth wireless adapter is designed to perform the same job as the 802.11b adapter installed in your Windows PCs. It isn’t.
Bluetooth wireless technology is vastly different from 802.11b wireless LAN technology. Not only is it significantly slower than 802.11b products, but it’s also completely incompatible with them. To better understand this, let’s take a look at what Bluetooth technology is and what exactly it was designed to do.
Bluetooth is a telecommunications industry specification that describes how mobile phones, computers, and personal digital assistants (PDAs) can be easily interconnected using a short-range wireless connection. Bluetooth products achieve this by placing a small, inexpensive radio transmitter/receiver module in each electronic device. This module acts as the physical medium to connect these devices and also provides the necessary communication protocols needed for these devices to successfully transmit data.
For the user, there are three main benefits to using this technology. First of all, it’s wireless, so when you travel you don't have to worry about carrying a multitude of connectors and attachments with you just to connect your peripherals. Next, it’s very inexpensive, so it won’t cost you an arm and a leg to take advantage of it. Finally, Bluetooth doesn't require you to do anything special to make it work. The devices find one another and strike up a conversation without any user input at all. This makes it ridiculously simple to connect previously complicated electronic devices.
For example, your computer connects to your keyboard through a dedicated keyboard port. Your mouse uses the PS2 port, your PDA the USB port, and if you had an older printer, it would need to be connected to your PC’s parallel port. All of this means you not only need to know what ports to connect each of these devices to, you also need to know how to configure them.
Even if this isn’t an issue for you, sometimes just physically connecting these devices to your PC can be problematic. If your PC is on a desk, this isn’t a big deal. If, however, your PC is housed in a wall unit, it could be much more difficult. Not to mention the added expense of purchasing the needed cables or the fact that the length of the cable limits how far you can place a device from the PC.
Bluetooth-equipped hardware does away with all this because each of these devices can contain a Bluetooth chip that will wirelessly connect them to the PC without any interaction necessary from the user. Furthermore, since these are wireless devices, items like the PDA or printer now have the ability to be placed and used anywhere in the room.
Bluetooth devices operate in the 2.45 GHz (Gigahertz) frequency range. Other devices currently operate in this frequency range as well, including cordless phones, baby monitors, and garage-door openers (to name just a few). One of the ways that Bluetooth devices avoid interfering with these other systems is by sending out a very weak 1 milliwatt signal (a cell phone by comparison can transmit up to 3 watts). This low power limits the range of a Bluetooth device to about 10 meters.
A frequency hopping scheme allows devices to communicate even in areas with a great deal of electromagnetic interference. In addition to data, up to three voice channels are available, and each device is assigned a unique 48-bit address. Connections can be point-to-point or multipoint. Bluetooth devices have a maximum transmission rate of only 1 Mbps (up to 2 Mbps in the second generation of the technology), of which about 20 percent of this capacity is used for data headers and handshaking information.
By comparison, Wi-Fi wireless LAN adapters are much more powerful and capable of reaching data transmission rates approaching 54Mbps. The most popular Wi-Fi standard is the one used in your D-Link router, 802.11b. This version provides users with 11 Mbps transmission speeds and also operates in the 2.4 GHz band. Products based on this specification have very good range and can commonly transmit data at distances of well over 100 feet.
The most recently introduced specification, 802.11g, offers users the best of both worlds by providing users with higher transmission rates yet 100% compatibility with existing 802.11b products, which means your current investment in 802.11b technology would not be lost if you later decide to upgrade a few of your systems to the new “G” standard. Wi-Fi products also have strong security protocols, which make them a better network solution.
So as you can see, Bluetooth and Wi-Fi wireless technology were designed for two completely different purposes. Bluetooth products make it easy to connect various electronic devices to each other without the need for clumsy cables, while 802.11x Wi-Fi products were designed as a replacement for (or extension of) the wired LAN.
I took the liberty of looking up the specifications for your PowerBook and discovered that it currently is not equipped with a Wi-Fi adapter. However, it is AirPort-ready (AirPort is Apple’s nomenclature for Wi-Fi products), so it can be easily upgraded with wireless network functionality. The Apple AirPort Extreme card can be purchased for about $100 at the Apple Store. (You may be able to find it even cheaper elsewhere.)
Incidentally, the AirPort Extreme card your laptop uses is actually an 802.11g product, so it can support data transfer rates up to 54Mbps. Your current D-Link router is an 802.11b product, which means the highest transfer rate that it will support is 11Mbps. This will work with the AirPort, but at some point you may want to consider upgrading to a G class router. This would still be compatible with your 802.11b notebooks while enabling your PowerBook to run at full speed.
I hope this helps to clarify things for you. If you’d like to find out more information on Bluetooth technology, I’d suggest you visit the official Bluetooth site at www.bluetooth.com. Back in April I wrote a Q&A column that discussed the various flavors of the 802.11x specifications in a bit more detail. If you’re interested, it can be found here. Even more detailed information can be found here.
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