Campbell Scientific NL240 Wireless Network Link Interface - Manual (Page 20)

NL240 Wireless Network Link Interface
Compliance
RoHS Compliant
Complies with the limits for a Class B digital device, pursuant to part 15
of the FCC Rules.
Contains an embedded radio transmitter with the following approvals:
FCC Identifier: XF6-RS9110N1102
Industry Canada: 8407A-91101102
Europe ETSI EN 301 489-17 V1.2.1:2002
Europe ETSI EN 300 328 V1.7.1:2006
6. Wi-Fi
6.1 Introduction to Wi-Fi for WLANs
Wi-Fi is a technology that allows data transfer among electronic devices using
specific radio frequencies over a wireless local area network (WLAN). A
wireless network is like a wired network, except it uses radio waves just like
cell phones, televisions, and other radios. Over-the-air speeds vary depending
on protocol, distance, and network activity. When using the NL240, please
note that your total throughput to the datalogger will generally be governed by
the speed of serial communication.
Wi-Fi transmits at frequencies around 2.4 and 5 GHz (the NL240 only uses 2.4
GHz). The high frequency allows fast rates but reduced communication
distance. These frequencies can be used by anyone and do not require a license
from the FCC to use or transmit (unlike most UHF and VHF frequencies) as
long as certain power levels are maintained.
The NL240 supports the 802.11b, 802.11g, and 802.11n wireless network
standards.
The NL240 Wi-Fi device also supports several wireless security protocols.
These include WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected
Access)(personal) with TKIP (Temporal Key Integrity Protocol),
WPA(personal) with AES (Advanced Encryption Standard), WPA(personal)
with TKIP+AES, WPA2(Wi-Fi Protected Access II)(personal) with TKIP,
WPA2(Wi-Fi Protected Access II)(personal) with AES, and WPA2(Wi-Fi
Protected Access II)(personal) with TKIP+AES. These security protocols
allow network traffic to be encrypted and help protect data transmitted over the
Wi-Fi network.
6.2 Wireless Network Modes
The NL240 works in two types of wireless modes, infrastructure and ad hoc.
In infrastructure mode (see FIGURE 6-1, Infrastructure network), the NL240
connects to an already established wireless network (WLAN). This wireless
network is usually controlled by a single Wireless Access Point (WAP). This
WAP will typically connect the wireless network (and the NL240) to a larger
wired company or home network and/or the internet. The WAP device also
controls and routes all the traffic on the wireless network. The WAP,
furthermore, controls security for network access, the wireless frequency
(channel) to use, and has the pre-established Service Set Identifier (SSID) for
the wireless network. Infrastructure mode wireless networks are usually the
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