For 802.11b and 802.11g products use the radio frequency in the 2.4Gz band the band used by cordless phones, The 802.11a products use the 5.8Gh band used by the less common group of phones The 11Mps and 54Mps are not what you actually get.
Typical wireless speeds for 802.11b products is about 4-5 Mbps and the 802.11g have an capacity of about 20Mbps and the 802.11a are about 22Mbps.
Just about enough speed for modern applications for example watching BBC TV abroad like in this video.
It’s not uncommon in the computer industry to exaggerate a little about the speed of their devices, after all is a 17-inch monitor really 17 inches, a 80GB disk drive 80 Gigs and I know that modem of yours doesn’t deliver 56Kbps bits to your computer.
The main reason for the wireless speeds inflated rating is that some of it is taken by overhead, and even these lower capacities can be limited by distance-walls and other environmental conditions.
54 Mbps and 11 Mbps, 8+3 non-overlapping channels, 64 users per access point, 2.4 GHz and 5 GHz Dual-band products – Linksys – WPC55AG – 54Mbps 802.11g/b/a Wireless Cardbus Adapter are a good choice in environments that are just getting started with 802.11b networks but expect that faster speeds will soon be needed.
Dual-band products offer both 802.11b and 802.11a functionality, in both PC Cards USB ports and AP products, enabling WLANs that can accept both types of clients. Dual-band clients automatically search for the best connection as users roam throughout the office or campus environment. Dual-band offers the best of both worlds.
Simultaneous operation: Both 802.11a and 802.11b technologies operate side-by-side, without interference. Users can select either band, or both.
The same WLAN adapter can be used in more places, such as home, work, and public hot spots, without configuration changes. Highest density: Up to 11 channels from both protocols are available, supporting more users.
Protects WLAN investment, supports both high- and low-speed network devices. Easier administration: Dual-band units combine two technologies into one, easing administration and support costs in environments where both types of devices are needed. Less interference: Devices have more channel options available.
Many dual-band products feature improved security capabilities, enhancing the WEP standard and offering additional functions such as MAC address filtering.
Where It Should Be Used
Dual-band products offer the best of both worlds
Anywhere there is an existing WLAN infrastructure that may need to accommodate both 802.11a and 802.11b USB devices. Will also support 802.11g devices. Density: Wherever maximum density is needed, dual-band is the right solution. Dual-band products have more channels (11), so they can support more users. This can result in a lower deployment costs.
Dual-band offers maximum wireless speed and maximum range. A single configuration can support both network protocols, reducing the need to support multiple environments or reconfigure client devices as users move between them. This results in lower support costs.
Include businesses where offices are co-located with warehouses, large campus environments, people traveling between multiple WLAN network types, or any organization that wants to extend existing WLAN to support the other protocol.
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