AMX NXD-CV7 - Manual (Page 64)

Configuring Communication
56 7" Modero Widescreen Touch Panels
communication parameters must match those of the pre-installed wireless interface card installed
within the panel. The CV7 touch panels allow users to connect to a wireless network through their
use of the optional AMX 802.11b wireless interface card. This internal card transmits data using
the 802.11b signals at 2.4 GHz. Before beginning, there are several concepts that should be
explained:
Wireless Access Points are the cornerstone of any wireless network. A Wireless Access
Point acts as a bridge between a wired and wireless network. It aggregates the traffic
from all the wireless clients and forwards it down the network to the switch or router.
One Wireless Access Point may be all you need. However, you could need more Wireless
Access Points depending on either how large your installation is, how it is laid out, and
how it is constructed.
802.11b/2.4 GHz vs. 802.11a/5 GHz are the two major WLAN standards and both
operate using radio frequency (RF) technology. Together the two standards are together
called Wi-Fi and operate in frequency bands of 2.4 GHz and 5 GHz respectively.
The 802.11b specification was the first to be finalized and reach the marketplace and at
this time is the only specification supported by the Modero line of products. The actual
throughput you can expect to obtain from an 802.11b network will typically be between
4 and 5 Mbps.
When indoors, 802.11b signals can travel as far as 150 meters (492 feet). The outdoor
802.11b range is over three times greater; 500 meters (1640 feet, or nearly 1/3 of a mile).
At either of these extreme ranges, the bandwidth available is at least 1Mbps. To operate
in its maximum bandwidth mode of 11 Mbps, the distance indoors can be no more than
50 meters (164 feet); outdoors it should be 250 meters (820 feet).
Because of the higher frequency (and thus shorter wavelength) that they use, 802.11a
signals have a much tougher time penetrating solid objects like walls, floors, and ceilings.
As a result, the price for 802.11a's higher speed is not only shorter in range but also a
weaker and less consistent signal.
Wireless Equivalent Privacy (WEP) Security is a method by which WLANs protect
wireless data streams. A data stream encrypted with WEP can still be intercepted or
eavesdropped upon, but the encryption makes the data unintelligible to the interloper. The
strength of WEP is measured by the length of the key used to encrypt the data. The longer
the key, the harder it is to crack.
802.11b implementations provided 40-bit and 104-bit WEP keys. This is known
respectively as 64-bit and 128-bit WEP encryption. 64-bit is generally not regarded as
adequate security protection. Both key lengths are supported by the Modero product line.
Whichever level of WEP you use, it's crucial to use identical settings (CASE
SENSITIVE)--the key length, and the key itself-- on all devices. Only devices with
common WEP settings will be able to communicate. Similarly, if one device has WEP
enabled and another doesn't, they won't be able to talk to each other.
Although the calculations required to encrypt data with WEP can impact the performance
of your wireless network, it's generally seen only when running benchmarks, and not
large enough to be noticeable in the course of normal network usage.