User's Manual

Reference Manual for the Model FWAG114 Cable/DSL Wireless ProSafe Firewall
Wireless Networking Basics D-9
Note: The available channels supported by the wireless products in various countries are different.
For example, Channels 1 to 11 are supported in the U.S. and Canada, and Channels 1 to 13 are
supported in Europe and Australia.
The preferred channel separation between the channels in neighboring wireless networks is 25
MHz (5 channels). This means that you can apply up to three different channels within your
wireless network. There are only 11 usable wireless channels in the United States. It is
recommended that you start using channel 1 and grow to use channel 6, and 11 when necessary, as
these three channels do not overlap.
802/11a Legal Power Output and Wireless Channels
IEEE 802.11a utilizes 300 MHz of bandwidth in the 5 GHz Unlicensed National Information
Infrastructure (U-NII) band. Though the lower 200 MHz is physically contiguous, the FCC has
divided the total 300 MHz into three distinct domains, each with a different legal maximum power
output. Below is a table of summary for different regulatory domains.
Table D-3: 802.11a Radio Frequency Channels
Note: Please check your local Authority for updated information on the available frequency and
maximum power output.
IEEE 802.11a uses Orthogonal Frequency Division Multiplexing (OFDM), a new encoding
scheme that offers certain benefits over a spread spectrum in channel availability and data rate.
The 802.11a uses OFDM to define a total of 8 non-overlapping 200 MHz channels across the 2
lower bands; each of these is divided into 52 sub carriers and each carrier is approximately 300
KHz wide.
U-NII Band Low Middle High
Frequency (GHz) 5.15 – 5.25 5.25 – 5.35 5.725 – 5.825
Max. Power Output 50 mW for US
200 mW for Can-
ada, Europe,
and Australia
250 mW for US
200 mW for Europe and Australia
1 W for Canada
1 W for US and Australia
4 W for Canada
25 mW for Europe