These products are used to connect one device to a wireless network, much like an Ethernet network interface card (NIC). Most of the adapters can work either in a peer-to-peer network (this is called Ad Hoc mode), or through an Access Point that connects to a larger, usually wired, network (Infrastructure mode). HomeRF based devices also support both methods of communication, but switch methods on the fly.

PC Card
This format is familiar to laptop and PDA users and comes in 16bit and CardBus (32 bit) forms. Unfortunately, manufacturers often don't tell you which technology they use, so if your laptop supports only CardBus adapters, you may have do experiment to find out whether a product will work for you. PC Cards have been the format of choice for laptop users, but have the disadvantages of relatively high power usage and poor antenna orientation.

USB
Our method of choice for connecting desktop machines. These adapters have the advantages of no-opening-the-box installation and a cable connection that allows positioning the adapter's antenna for optimum signal. The biggest negative is that you may experience the same driver related problems that plague other USB devices.

Unless you have many active USB devices attached to your computer, you don't need to worry about USB's speed limitation, since most 802.11b adapters' maximum throughput is about 5Mbps compared to the 8Mbps or so that you'll get from most USB host adapters.

PCI and ISA
Given the other choices available, these internal card format devices are quickly fading away. Most manufacturers sell you a separate PCI adapter to use with their standard PC Card wireless adapter, and you'll have to hunt to find companies who also offer an ISA bus adapter.

Built-In
There are not many nice things that we can say about this method. It's more costly, installations tend to difficult, and the resulting antenna orientation (sticking horizontally out the rear, low to the floor, and pointing toward an outside wall) is usually terrible for performance! If you do choose this method, buy your adapter from the same company as your PC card radio. No manufacturer will support the use of another's radio card in their adapter.

The main disadvantages are that this option is usually the most expensive one, and that you are limited to the one adapter that your notebook's manufacturer selects. If you go this route, also check to see how difficult it is to power down the wireless connection. You'll definitely want to do that when you don't need it, since an 802.11b radio can easily cut your notebook's battery life in half, even if you are not actively using the card.

Product Types - Access Points (AP) and Bridges

Access Points
In its generic form, an Access Point is a wireless transceiver that connects a wired LAN with wireless clients. An AP makes this connection in a way that makes the wired and wireless clients appear to be in the same network.

 NOTE: An AP in its basic form can only connect to wireless clients, and not to another AP.

This category of devices can get confusing, given the way that some manufacturers have named their products and enhanced their feature sets to include "bridging" features. See the next section for more info.

Bridges
The generic networking term "Bridge" refers to a device that connects two LANs. Therefore, when you want to connect two (or more) LANs via a wireless connection, use wireless bridges.

But beware! This product category is probably the most confusing, and holds the most potential for a customer to choose a product that doesn't really do what they require. For example, a number of manufacturers have added bridging features to their Access Points and not renamed their products (Linksys WAP11), or called their products bridges when they also support Access Point functions (SMC 2682W). There are also "bridge" products that support only one attached device. Our only advice here is to read the product feature description very carefully and don't rely on the name of a product to tell you what it does.

Once you select a product, you'll have to configure it. There are a number of wireless bridging modes, and of course, manufacturers have not used the same terminology. Let's see if we can untangle things a bit:

• Point-to-Point - The simplest bridging mode where one bridge unit talks to another. You usually enter the MAC address of the unit on the other end of the connection in each bridge's configuration screen. Manufacturers are pretty consistent in describing this mode and the way it's set up.

• Point-to-Multipoint - This mode allows multiple networks to be connected. The modes used in the setup vary from manufacturer to manufacturer. SMC's 2682W, for example, requires one unit to be set as a "Bridge Master", and the other bridge units to be set as "Bridge Slaves". Linksys' WAP11 has you set one unit to Point-to-Multipoint, and the others to Point-to-Point mode, with the "Remote MAC address" set to the MAC address of the box set to Point-to-Multipoint mode. Confused? Wait, there's more...

• AP plus Bridging (AP Client) - Manufacturers try to confuse you on this feature, but in theory, it's simple. It's basically a mode that sets a bridge to work with an Access Point, instead of another bridge. Manufacturers are fuzzy on the details of how this works, but one result is to create a wireless Client Adapter that has an Ethernet output. Another possibility is to create a network where your "local" AP supports wireless clients and wirelessly connects to an Ethernet based LAN, i.e., more than one Ethernet client. In this mode, however, the "remote" end of the connection can't talk to wireless clients. To do that you need to find a product that supports the next mode...

• Wireless Repeater - Access Points normally require an Ethernet connection when multiple units are used to extend the range of a wireless LAN. Wireless repeating eliminates the need for the Ethernet cable, and allows multiple APs to both connect to wireless clients and to other APs that support wireless repeating. This is a very nice feature to have, but you'll pay for it, since it's typically only available on products priced above $500. A cheaper way to go is actually to connect two of the less expensive AP/Bridges together.

As if all the above weren't confusing enough, there are also products that allow devices that have only an Ethernet or serial connection to be added to your wireless network. 3Com calls theirs an Ethernet Client Bridge, while Linksys' product goes by the "Wireless to Ethernet Adapter" moniker (Linksys WET11). Client Adapter or Bridge? You decide!

Product Types - Wireless Routers

After all the confusion in the Access Point / Bridge category, you'll find Wireless Routers easy to understand! Wireless routers combine the connection sharing features of a router with those of a wireless Access Point. Most products take a basic router, steal one of the LAN Ethernet ports, and internally connect it to a radio module. They then add AP functions to the router's firmware.

The main difference between a wireless Router and Access Point is that an Access Point doesn't provide firewall or Internet connection sharing and a Wireless Router does.

 NOTE: It's possible to use a wireless router as an Access Point. Just disable the router's DHCP server and use only the LAN ports to connect your Ethernet devices.