| Getting un-Wired with IEEE 802.11 |
 Overview |
|
Are you ready for the convenience that comes from
sending your Ethernet packets over the air instead of through a
wire? Wireless is not for everyone,but if your application uses
mobile equipment that is controlled over a TCP/IP network,or the
cost of installing wire conduits at your work site is prohibitive,
then consider setting up a wireless local area network (WLAN). The
IEEE 802.11 standard established a way to use radio frequency (RF)
technology to send Ethernet packets over the air. Applica tions
that include TCP/IP will run on 802.11-compliant WLANs the same
as they do over Ethernet.By common agreement between regulatory
agencies around the world (FCC,ETSI,etc.), a WLAN transmits over
unlicensed spectrums,with only minor variations from country to
country. |
| 802.11
Specifications |
| |
802.11b |
802.11g |
802.11a |
| Approval
Date |
Sept.1999 |
June 2003 |
Sept.1999 |
| Compatibility |
IEEE 802.11b compliant |
IEEE 802.11b and 802.11g
compliant |
IEEE 802.11a compliant |
| Number of Channels |
3 non-overlapping |
3 non-overlapping |
8 non-overlapping
(4 in some countries) |
| Data Rates |
11,5.5,2,and 1 Mbps |
54,48,36,24,18,12,9,
and 6 Mbps |
54,48,36,24,18,12,8,
and 6 Mbps |
| Wireless Medium |
Direct Sequence Spread
Spectrum (DSSS),2.4 GHz |
Orthogonal Frequency
Division Multiplexing
(OFDM),2.4 GHz |
Orthogonal Frequency
Division Multiplexing
(OFDM),5 GHz |
|
| Typical
Wireless Network Configurations |
|
A wireless LAN is configured for either Ad-hoc
mode or In frastructure mode.In Ad-hoc mode,stations use peer-to-peer
transmission to send information from station to station, without
requiring an AP (Access Point) to connect to a wired network. This
is the easiest and least expensive way to set up a wireless network.Alternatively,Infrastructure
mode requires using an AP.The AP can be used by itself to set up
a WLAN, or can be used to connect the WLAN to a wired network.In
either case, all wireless communication goes through the AP. |
 |
| Benefis
of using Wireless Technology |
| What makes wireless
networking a natural choice for many networking requirements?
Flexibility: Wireless networks work anywhere,anytime.
Easy Deployment: Wireless networks are ideal for
those hard to wire areas.
High Performance: Wireless networks have the bandwidth
and safeguards needed to keep essential applications running continuously.
Cost Effective: Wireless networks can be installed
quickly,and help reduce the cost of cabling and maintenance. |
| MOXA ’s Wireless Solution for Industrial Markets |
|
One of the biggest concerns raised by potential
users of WLAN technology is safety. Since data is transmitted by
radio waves, how can users guarantee the con ?dentiality of their
information? To provide secure transmission over wireless networks,
MOXA provides Wi-Fi Protected Access (WPA) security specifications
to overcome weaknesses in Wired Equivalent Privacy (WEP).In addition,
MOXA ’s wireless products incorporate several important features
to meet the stringent demands of industrial applications, including
redundant power inputs, operating temperature range from 0 to 60
°C,and DIN-Rail mounting capability. The enhanced reliability
of these products make them a great choice for your wireless industrial
applications. |
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