AML KDT900 User's Guide download pdf (Page 34)

KDT900 User’s Guide

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Interference and Coexistence

802.11 operates in a range of radio frequencies known as an "unlicensed" band (i.e., the

FCC does NOT require the use of a license in order to operate a radio transmitter in this

range). This means that commercially available radio devices other than wireless LAN

devices are permitted to use the same frequency band as 802.11. Consequently, these co-

existing radio devices can interfere or "jam" the wireless LAN (and vice versa). The most trou-

blesome devices are cordless telephones and microwave ovens.

Fortunately, higher quality cordless phones tend to "listen" for a clear channel before

becoming active and will thus avoid interfering with a wireless LAN (i.e., the cordless phone

seeks a clear channel for itself so naturally avoids being interfered with or being a source of

interference). Jamming from microwave ovens is more severe but is usually restricted to the

upper frequency range for 802.11 (it should be noted that 802.11b/g divides the available

frequency band into 11 channels [US]. The higher numbered channels are most susceptible

to microwave oven interference).

In each instance, jamming occurs only when the cordless telephone or microwave oven is

active.

Encryption and Authorization

Much has been publicized in the mass media recently about security problems with wireless

LANs. Although it cannot be denied that some encryption algorithms currently used in

802.11 are flawed, the fact is that security breaches of a wireless LAN require a deliberate

attempt to access the network by an intruder.

The primary issue is that many current users of wireless LAN have opted NOT to turn on secu-

rity features. If users were to enable the security features currently available (including only

allowing known systems access to the network and enabling WEP [Wired Equivalent Privacy]

or WPA [Wifi Protected Access]) on even the most basic access points, the intruder's work is

much harder. Much as a burglar will stray away from a house whose doors and windows are

securely locked, so too will an attacker tend to move past a wireless network when even

the simplest security measures are enabled.

Wireless Configuration

The optional 802.11b/g/n radio can be configured with the KDT900 Setup Utility under the

Windows Wireless setup screens.

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AML KDT900 User's Guide Page 34