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4
AP-12 MANAGER
4
DD
Communication channels
Set the communication channels of network groups at least four channels apart to
avoid interference if two or more access points are available in the wireless trans-
mission area.
Otherwise, interference may occur due to partial overlap in bandwidth as shown below.
Channel settings of 1-6-11, for example, eliminates the possibility of interference.
2400
2410 2420 2430 2440 2450
Frequency (MHz)
2460 2470 2480 2490 2500
1 channel
2 channel
3 channel
4 channel
5 channel
6 channel
7 channel
8 channel
9 channel
11 channel
10 channel
DD
Hidden wireless terminals
During Access Point mode communication as shown below, wireless LAN termi-
nal [A] and [C] cannot communicate directly, even when both terminal [A] and [C]
can access AP-12 [B].
In such a case, terminal [A] is a “Hidden wireless terminal” for [C], and terminal [C]
is a “Hidden wireless terminal” for [A].
When terminal [A] is accessing AP-12 [B], for example, to prevent the communi-
cation collision, the request-to-send (Rts) signal received by AP-12 [B] sends a
clear-to-send (Cts) signal to both terminal [A] and [C] repeatedly. Then terminal [C]
recognizes that AP-12 is busy, and forbidding to access to AP-12 [B].
Ethernet LAN
A
B
AP-12 [B]
wireless transmission area
AP-12 [B]
wireless transmission area
C
Communication
collision
wireless LAN [A]
wireless transmission area
wireless LAN [C]
wireless transmission area
AP-12
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