User Manual

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Differentiating Between Wireless Technologies
1.4 WLAN vs. Proprietary 2.4GHz
Common usage of the WLAN limits its distance to under 100 meters. Now with Moxa’s advanced technologies, it is
also possible to extend the distance up to 10 kilometers for multi-point connections or 20 kilometers for point-to-
point connections.
The IEEE 802.11 standard is designed for high-speed data transmission. However, it is also vulnerable to outside
interferences. This is unacceptable for some industrial applications where the control elements are often involved.
It is a basic control requirement that communication must not be interrupted. To meet this requirement, there are
some proprietary 2.4GHz band wireless devices that use FHSS spread spectrum technologies to meet the needs
for higher noise resistance. In summary, FHSS sacrifices throughputs and communication ranges for more stability.
Table: WLAN vs. Proprietary Wireless
Moxa Banner
Frequency 2.4 GHz (ISM) 900 MHz (license needed) 2.4 GHz (ISM)
Standard IEEE 802.11 Proprietary Proprietary
Spread Spectrum DSSS / OFDM *a FHSS FHSS
Throughput 22 Mbps 115200 bps 115200 bps
Distance 10 km > 10 km 3.2 km
Communication method Point to multiple points Point to point Point to point
*a: FHSS utilizes frequency hopping to avoid signal interference. Bluetooth is one example that uses this
technology. In the early days, IEEE 802.11 also used FHSS but has since adopted DSSS (Direct Sequence Spread
Spectrum) out of security concerns. 802.11a, 801.11g, and 802.11n adopt OFDM to increase their resistance to
external interferences.
About modulation and spread spectrum, please refer to Chapter 2.1
WWAN vs. WLAN vs. WPAN vs. Proprietary RF
Technologies WWAN WLAN WPAN Proprietary RF
Standard
GSM/GPRS/CDMA/
WCDMA/WiMax
IEEE802.11
Bluetooth/
ZigBee
No Standard
Connection
Mode
Point to point (GSM)
WAN (GPRS/3G)
LAN (TCP/IP) Point to point Point to Point
Communication
coverage
5 km to 30 km 100 m to 300 m Approx. 10m
100 m to 100
km
Security High High Medium
Low (not
standard)
Throughput 50 kbps to 100 Mbps
54Mbps (802.11a/g),
600 Mbps (802.11n)
115200 bps
115200 bps to
1 Mbps