ZyXEL Communications B-420 User Manual

ZyAIR B-420 Wireless LAN Ethernet Adapter and Bridge 

Wireless LAN and IEEE 802.11                                                                                                   D-1            

A wireless LAN (WLAN) provides a flexible data communications system that you can use to access 
various services (navigating the Internet, email, printer services, etc.) without the use of a cabled 
connection. In effect a wireless LAN environment provides you the freedom to stay connected to the 
network while roaming around in the coverage area. WLAN is not available on all models. 

Wireless LAN offers the following benefits: 

1.  It provides you with access to network services in areas otherwise hard or expensive to wire, such as 

historical buildings, buildings with asbestos materials and classrooms. 

2.  It provides healthcare workers like doctors and nurses access to a complete patient’s profile on a 

handheld or notebook computer upon entering a patient’s room. 

3.  It allows flexible workgroups a lower total cost of ownership for workspaces that are frequently 

reconfigured. 

4.  It allows conference room users access to the network as they move from meeting to meeting, getting 

up-to-date access to information and the ability to communicate decisions while “on the go”. 

5.  It provides campus-wide networking mobility, allowing enterprises the roaming capability to set up 

easy-to-use wireless networks that cover the entire campus transparently. 

The 1997 completion of the IEEE 802.11 standard for wireless LANs (WLANs) was a first important step 
in the evolutionary development of wireless networking technologies. The standard was developed to 
maximize interoperability between differing brands of wireless LANs as well as to introduce a variety of 
performance improvements and benefits. On September 16, 1999, the 802.11b provided much higher data 
rates of up to 11Mbps, while maintaining the 802.11 protocol. 

The IEEE 802.11 specifies three different transmission methods for the PHY, the layer responsible for 
transferring data between nodes. Two of the methods use spread spectrum RF signals, Direct Sequence