What is Wifi? - What is a Wireless Card?

Basically, a wireless card, more technically referred as a wireless network interface controller or wireless network interface card (WNIC), is any device that acts as an interface between incoming signals from a wireless network and the rest of the computer.

More specifically, a wireless card acts as an intermediary for the data packets sent out by a wireless router, a portion of the device devoted to being an antenna to both receive and transmit these signals.

Now, remember that there are many wireless standards out there, including wi-fi and Bluetooth. Each of these standards vary in several ways, including the specific frequencies they use in the radio portion of the spectrum. Given current technological development, any given wireless card is specially made to work within one of these standards. That is, a wifi adapter will not also work for Bluetooth. The rate at which data transfer with wireless works varies greatly, from 2 to 54 Mbit/s, depending on ooth the wireless router and your wireless card.

Most wireless cards can be placed into one of two modes: an infrastructure mode and an ad-hoc node. In the infrastructure mode, the wireless card can connect to some sort of access point to a wired network, such as to the Internet. In ad-hoc mode, the wireless card can connect to any other wireless nodes available, such as other computers.

A further variation in wireless cards is the form in which they take. Tthere are many types of wireless cards, each catering to a separate market amongst computer users.

The most flexible of these wireless cards connect to the computer via a USB cable, and are sturdy enough that they will not easily break despite their external nature. This was developed mostly to retrofit computers with wireless capability that otherwise simply did not have the hardware ports to do so. These are generally called “dongles”, though the term is sometimes used to apply to other USB devices.

The PC card adapter is a less invasive option for many computers, especially laptops. This device slides into the PC card slot in computers that are equipped with it, and have a small antenna on the inside. These tend to protrude slightly from the computer, which for laptops increases the danger that it could be damaged.

For desktop computers, there are also wireless cards that connect directly to the PCI bus, or peripheral component interconnect. As the name states, this is a port used for connecting peripheral devices to the main part of the computer. However, these are not as popular as they used to be, nor are they of any use to laptop computers.

External wireless adapters were also created for many other devices, such as the PDA, though these never caught on to quite as much usage.

Increasingly, more and more computers (and devices in general) come with internal wireless cards that are not easily accessible, being built into the device.

For more information on the devices that enable wifi technology, as well as wifi in general, check out the rest of the What is wifi? series.