A wireless local area network (WLAN) modem is a radio frequency (RF) device that allows local computers to communicate with each other wirelessly. It also allows all computers on the network to share a single Internet connection. A traditional WLAN modem sits on a desktop to serve networking connectivity to the home, commercial building, or general locale. There are also mobile wireless modems that provide an access point or hotspot on the go.
A WLAN modem comes with a built-in router to direct traffic on the local network. The router keeps track of the origin of requests and funnels responses to the appropriate machine by reading data packets with unique address information. The router also handles requests made to and from the Internet when a connection is available.
In order to communicate with a WLAN modem, computers require a wireless network card. The card consists of a radio transmitter and receiver, much like the WLAN modem. The network card does not include a router, as it is only designed to connect a single computer to the network. Network cards are typically internal, but external wireless network adapters can also be purchased.
Wireless communication protocols are standardized so that competing manufacturers can produce products that will interoperate. Standards are set by the Institute of Electrical and Electronics Engineers (IEEE), a non-profit, international group. Protocols follow a numeric designation of 802.11, followed by a letter signifying the exact flavor of the protocol. For example, 802.11a, 802.11b, 802.11g and 802.11n are four wireless standards, with the last two being the most recent incarnations. Wireless network cards must share at least one common 802.11 standard with the WLAN modem in order to successfully exchange data.
The Wi-Fi™ Alliance is an international group that promotes wireless technology. It certifies submitted products as Wi-Fi™-compliant when those products meet stringent standards of interoperability. Products can then carry the Wi-Fi™ logo of approval. Devices that carry the logo are essentially guaranteed to work together for potentially smoother running networks. A true Wi-Fi™ network consists solely of certified hardware.
Wi-Fi™ certification is not free to manufacturers so Wi-Fi™ approved hardware is more expensive. In general, businesses might opt for a Wi-Fi™ network, while the extra money is probably wasted on most home networks. A WLAN modem that is not certified will typically be less expensive.
In addition to the desktop WLAN modem, a mobile access point or roaming hotspot is created by a wireless modem that is designed to go on the road. These compact modems come in different footprints from USB dongles to sleek cards, utilizing cellular technology to provide Internet access to multiple devices. An account with a cellular carrier is required.
When shopping for a WLAN modem, note the wireless protocols or cellular standards the device supports to be sure it will be compatible with existing network cards or devices. To future-proof the investment, it is best to buy a product that supports the latest standards, though backward compatibity with a previous standard can also delay the need to update older cards or products.