User manual

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Cooper Bussmann 245U-E Wireless Ethernet Modem & Device Server User Manual
21Rev Version 2.19
Figure 19 Channel Separation
Only one of these channels is used at a time and is configured at the access point, The access point then uses
this channel to send out beacon transmissions and connections. Clients scan all channels for a suitable access
point and then adopt the same channel as the access point when a connection is established. Figure 20 shows the
RFenergy distribution for the 802.11b/g transmission.
Figure 20 2.4-GHz Frequencies
On the 20-MHz channel (green), most of the energy is transmitted within the channel but some of the energy is
transmitted on the channels on either side, therefore causing interference on the these channels. The 10-MHz
channels (orange) are similar, with half of the energy overlapping into the next channel, but you can configure up
to 6x non-interfering channels at the same time. The 5-MHz channels (blue) do not overlap, so all 13 channels can
be used at the same time. There is also a single 40-MHz Channel (purple) that takes up over half of the full 2.4-GHz
band, and is therefore much more susceptible to interference from other channels.
If there is more than one 802.11 access point within the same wireless range, it is important that the access points
are on channels that are as far apart as possible. If there are two 20-MHz channel access points, set them to
channel 1 and 11. If there are three, set them to 1, 6, and 11.
802.11a (5 GHz)
The 245U-E-A utilizes frequency bands within the range of 5.15 GHz and 5.825 GHz. This is broken into 4 distinct
U-NII bands, and each region (for example, EU, US, AUS, NZ) has their own power and operational constraints.
See“Appendix C - CHANNELS” for details.