MobileTechReview.com: PDA WiFi - 802.11b wireless networking for PDAs

Local area wireless networking, generally in the form of WiFi (also known as 802.11b and 802.11g) is a hot topic. Companies, universities and home users are setting up wireless access points and running notebook computers without network wires. Even Starbucks, other coffee houses, airports, hotels and some small towns are installing WiFi for visitors. 80211hotspots.com has a listing of many sites around the US where you can access public wireless networks. So why not go wireless with your PDA? It makes perfect sense to free the most portable of all computers from wires. All you need is a fast Internet connection (DSL, cable model or wired Ethernet) and a WiFi access point to get started. Many PDAs and notebooks come with built-in WiFi, and if not, you can always buy an add-on card.

What is WiFi?

WiFi is the "friendly" term for the 802.11b (as well as 802.11a and 802.11g) Ethernet standard. It's the cousin to standard 802.11 wired networking and runs at a maximum of 11 megabits/second. That's plenty fast enough for most computer users, and more than fast enough for PDA users. It runs in the 2.4 gigahertz spectrum and shares that spectrum with microwave ovens, Bluetooth, some satellites and 2.4 gigahertz cordless phones. WiFi has a range of approximately 150 feet. Plenty enough range for the household (even good if you want to take a stroll in the back yard) and it can even penetrate walls. In corporate and university settings, several base stations and antenna amplifiers are installed to cover the large spaces and even courtyards of the average large business.

It won't cost you an Arm and a Leg

Base stations are now very affordable, with reliable brands such as D-Link, Apple and Linksys selling for around $100 or less. Wireless 802.11b SD network cards for Pocket PCs run around $60 to $100 and notebook PC cards cost even less. MostWindows Mobile Pocket PCs,Pocket PC phones, some MS Smartphones and several Palm models such as the LifeDrive and Tungsten T|X have built-in WiFi, while other Palms such as the Zire 72, Tungsten E2 and Tungsten T5 can use Palm's SD WiFi card which is sold separately. If you're interested in a Windows Mobile Pocket PC with WiFi, check out our comparison tables which list models with built-in WiFi.

Security

There have been articles published discussing security flaws in 802.11a/b/g. That doesn't mean it's a totally insecure medium. Transmitted data is scrambled. And if you choose to use encryption, the data is even harder to read. Encryption is available in two strengths: 64 bit (which really runs at 40 bit) and 128 bit encryption being the strongest available. You can tell your base station who's allowed to connect and who isn't. If a hacker is using a wireless network device to listen in on your traffic and she's good at hacking, she might be able to intercept and read your data as it's transmitted over the air. However, she'd had to be within range of your network, yet manage to not be noticed by others. Not all that easy, after all. However, if you're setting up a WiFi network in a corporate environment, take care that additional security measures (use WPA or VPN) are used whenever sensitive data is being transmitted over the airwaves!

What about 802.11a and 802.11g?

802.11a access points and cards are still on the market now, though they've become less common because they run at on a different radio band and are not backward compatible with 802.11b networking products so you'll have to upgrade everything if you're an existing 802.11b user. For now, the 802.11a network cards are 32 bit cardbus, which modern notebooks can use, but not PDAs because their expansion card bus is 16 bit. So don't hold out for the faster 802.11a if you're a PDA user!

802.11g, which is now prevalent, does run on the same band as 802.11b and is available in 16 bit card format. It took a few years, but 802.11g cards and integrated 802.11g are available for Windows Mobile PDAs and phones and Nokia S60 smartphones and handhelds. Keep in mind that PDAs don't transfer network data all that fast through their expansion card slots, so running at 802.11g's 54 megs vs. 802.11b's 11 megs won't make much of a difference to you. You will see a few hundred k increase in data transfer, and more importantly, your WiFi access point won't have to slow down to "b" speeds thereby slowing down your entire wireless network. You see, WiFi access points are both b and g compatible, but the access point will drop down to the slower b mode if even one 802.11b client (device) connects. So it's better to keep things at g if you can. That said, if you're running a 10baseT, DSL or cable modem network, you're limited to less than 11 megs, even in your wired network. The real advantage is sharing files between computers on the same network, say in your home or office, where data can move at 54 megs between these "local" machines, even though the outside connection speed to the Internet is limited by your DSL, cable modem or 10baseT network.

Our Environment

We use a variety of base stations (access points) for testing in our office. They support 64 and 128 bit encryption (encryption is often referred to as WEP (Wired Equivalent Privacy) when working with WiFi) which we use, and access control lists. When you use access control lists, only ethernet adapters whose MAC address is entered into the access list are allowed to connect to our network. A MAC address is a unique string of hex values. Each card has a unique MAC address from the factory. You need not use access control lists, otherwise known as MAC address filtering, but if you're concerned about the security of your wireless network, it's a good way of preventing strangers from hopping on your network.

Note: You'll find a variety of affordable base stations and wireless cards that support both 64 bit (which is actually 40 bit!) and 128 bit encryption, DHCP, NAT and access control lists. Most all of them have friendly user interfaces that make using these features easier than you think.

We use several notebook computers (Apple and Windows machines) and desktops in this environment along with a varying collection of PDAs and phones.

Our WiFi Card Reviews are listed in the left column.

Want to learn more about WiFi? Read our Primer.

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