Appendix D - Wireless Technology; Overview Of Wireless Technology - AMX NXD-1000Vi Operation/Reference Manual

Appendix D - Wireless Technology

Overview of Wireless Technology

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NXD-1000Vi 10" Modero® Wall/Flush Mount Touch Panel with Intercom
802.11b/2.4 GHz and 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. The actual
throughput you can expect to obtain from an 802.11b network will typically be between 4 and 5
Mbps.
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.
802.11g provides increased bandwidth at 54 Mbps. As part of the IEEE 802.11g specification,
when throughput cannot be maintained, this card will automatically switch algorithms in order to
maintain the highest spread possible at a given distance. In addition, 802.11g can also step down to
utilize 802.11b algorithms and also maintain a connection at longer distances.
IP Routing is a behavior of the wireless routing is largely dependent on the wired network interface.
Although the panel can be connected to two networks simultaneously it may only have one
gateway. If the wired network was successfully set up and a gateway was obtained; then the default
route for all network traffic will be via the wired network. In the event that the wired network was
not configured, then the default route for all network traffic will be via the wireless network. The
wired network connection always takes priority.
As an example: Imagine a panel connected to two networks A & B. A is the wired network and B is
the wireless network. If the Master controller is on either of these networks then it will be reached.
However if the Master controller is on a different network, C, then determining which network
interface (wired or wireless) that will be used is dependent on the gateway.
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.
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 64-bit and 128-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.
Appendix D - Wireless Technology
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