A dongle is a hardware device with a several different definitions. The term can refer to any hardware device that is small and connects to a computer via a port, while other more particular meanings include a device to safeguard the security of proprietary software; any key that is needed for program operation and connected to a port; or an adaptor cable made to link a wireless card to an Ethernet jack. A WLAN is a Wireless Local Area Network, a computer network operating in a small area, with or without Internet access. A WLAN dongle is a hardware device that enables separate computers to be linked in a WLAN.
A WLAN dongle operates under the IEEE (Institute of Electrical and Electronics Engineers) standard 802.11 for Wireless LAN. There are several versions of the 802.11 standard — a, b, g, and n — and it is important to match the standard to the networking needs and the equipment. The different versions operate on different frequencies — either 2.4 GHz, 5 GHz, or both — and at different speeds, and computers may be equipped with one or more of them. The 2.4 GHz range can experience interference from other devices, such as microwave devices, cordless phones, Bluetooth® devices, and baby monitors. In general, newer versions are faster, and one piece of equipment on an old standard can slow down the system.
There are usage requirements imposed by regulatory bodies when employing a WLAN dongle. The regulations stem from the Federal Communications Commission (FCC) in the United States and the R&TTE Directive (Radio and Telecommunications Terminal Equipment) in Europe, for example. Requirements typically cover safety concerns and technical requirements and are set out in user’s information accompanying the WLAN dongle. The number of channels will differ depending on where the equipment operates. For example, the channels used in Japan are 1–14, in France, 10–13, and in the United States, 1–11.
Two types of configurations are possible with a WLAN dongle. One is an ad hoc WLAN, which may also be called an Independent Basic Service Set (IBSS) and which makes communication between wireless clients possible. Some of the computers in the group may have dongles, while others have a WLAN PC card. The other configuration type is infrastructure mode. Infrastructure mode requires the existence of an Access Point (AP), which may be a router. It makes communication between both wireless and wired clients possible and also enables Internet.