A Layperson's Overview of Wireless Networking
“Wireless” is a term used to refer to network-type communications that take place without physical connections (wires).
The most basic type of wireless data transmission occurs through infrared, commonly known as “beaming.” Most handhelds have a built-in infrared port that is used to beam information from one infrared-enabled device to another. You can beam from one handheld to another, from a handheld to a desktop computer, or from a handheld to a printer.
The main advantage of beaming is that it doesn't require any additional hardware or software and so is “free.” Some of the disadvantages of beaming are that it is generally a one-way process and requires a line-of-sight connection, so you must aim your infrared port directly at the other device's port for the connection to be made. The range of infrared varies by device but is typically about six inches to four feet. Beaming is also a relatively slow way of sending data. For all of these reasons, beaming is good for small pieces of data, such as a business card, but not as good for larger amounts of data such as large applications or databases.
There are some third-party hardware and software systems, such as WebTarget™ Access Point by TriBeam Technologies and Bluefish Wireless™ Access Points, Servers, and Software, that enhance the built-in infrared capability of handhelds through stronger signals, as well as incorporating other features. Some of these products offer the ability to “mass beam” content to multiple users, while others offer two-way communication capabilities for Internet and email content. The ability to manage files for groups of students or even synchronize through this technology is likely to be developed further in the future. For some schools, these solutions may be valuable enhancements that help address classroom management issues.
The other types of wireless connectivity require some type of additional hardware purchase, such as expansion cards, access points, and/or service plans. One type of service is cellular, which is the same technology that is used with mobile phones. This type of wireless communication is typically used to facilitate long distance communications, such as phone calls. Examples of this type of wireless use include mobile phones, pagers, BlackBerry® devices, and Internet access via a handheld, such as a Palm or Handspring device. This type of service typically incurs a monthly service fee, which can range from $20 a month and up, depending on the nature of the service. Handhelds that use this technology include Palm's Tungsten W handhelds, Handspring's Treo communicators, and various other devices and add-on modules that have wireless modems.
Another type of wireless is that which connects to a LAN/WAN. An important thing to note about this technology is that it goes through walls and up and down stairs, so there aren't the line of sight issues that exist with infrared technology.
There are two main types of this technology:
Bluetooth — Bluetooth is a wireless solution with a range of 30 meters radius. Bluetooth works well for hard cable replacement, and as such, printing is likely to be the most important Bluetooth application. Bluetooth supports Ethernet, but because of its slow speed, this is not a typical use. Bluetooth supports voice, and this flexibility is likely to yield some popular applications, relating to automated phone switching between cellular and land line service. Bluetooth is also likely to be the technology used to enable cash-less vending machines and other purchases through cell phones or other Bluetooth-enabled devices.
802.11b (also known as Wi-Fi or “wireless Ethernet”) — 80211.b is a protocol used for wireless networking. It is great for locations, such as older school buildings, that are difficult (or expensive) to wire. The range for this technology is typically 150 — 300 meters in radius and supports up to 11 megabit data rates, which is very fast for Internet access and other applications. This is the technology that Apple is using for its Airport system, which is very popular with schools.
There are two basic configurations that can be used for local wireless access — Peer-to-Peer and Infrastructure. Peer-to-peer does not require a central access point; it works from device to device. Infrastructure uses a central access point or base station that connects to the network and can serve multiple devices within the specified radius.
802.11b supports both peer-to-peer and infrastructure use, but it is typically implemented in the latter way. In order to set up 80211.b in this way, two types of hardware are typically used: a base station or access point and a device card. There may be one or more access points, depending on how large of an area is to be served. The device card goes into each device (computer, handheld, etc.) that is to have wireless access. Typically, these device cards are in the form of a PC card or other similar device. Access points can cost from $100-400 and up. Device cards are typically around $100-200 each. Prices are expected to drop as the technology matures and economies of scale are achieved.
Bluetooth was designed to use peer-to-peer communications and is typically used this way. However, recently the notion of an access point has been added.
If is important to know that these various protocols are not compatible with each other. It is also important to note that within one type of technology, not all access points are compatible with all device cards. Because this is an emerging technology, compatibility testing should be done.
Here are some additional resources on wireless networking for schools:
