Advanced Configuration AP-700 User Guide
Interfaces
54
• 161: 5.805 GHz
• 165: 5.825 GHz
If you are using the unit in a country and band that require DFS, keep in mind the following:
• DFS is not a configurable parameter; it is always enabled and cannot be disabled.
• You cannot manually select the device’s operating channel; you must let the unit select the channel. You may make
channels unavailable by manually “blacklisting” them and preventing those channels being selected, in accordance
with local regulations or interference. You can also display the Channel Blacklist Table to view the channels that have
been blacklisted by the AP.
• In compliance with FCC regulations, the AP uses ATPC (Automatic Transmit Power Control) to automatically adapt
transmit power when the quality of the link is more than sufficient to maintain a good communication with reduced
transmit power. See Transmit Power Control/Transmit Power Level for more information.
DFS is required for three purposes:
1. Radar avoidance both at startup and while operational. To meet these requirements, the AP scans available
frequencies at startup. If a DFS enabled channel is busy or occupied with radar, the system will blacklist the channel
for a period of 30 minutes in accordance with FCC, IC, ETSI, and TELEC regulations. Once fully operational on a
frequency, the AP actively monitors the occupied frequency. If interference is detected, the AP blacklists the channel,
logs a message and rescans to find a new frequency that is not busy and is free of radar interference.
2. Guarantee the efficient use of available frequencies by all devices in a certain area. To meet this requirement, the AP
scans each available frequency upon startup and selects a frequency based upon the least amount of noise and
interference detected. This lets multiple devices operate in the same area with limited interference. This procedure is
done only at startup; if another UNII device comes up on the same frequency, the AP does not detect this or rescan
because of it. It is expected that other devices using these frequencies also are in compliance with country
regulations, so this should not happen.
3. Uniform Channel Spreading. To meet this requirement, the AP randomly selects its operating channel from the
available channels with least interference.
Affected Countries
Japan is certified in the TELEC regulatory domain, Canada is certified in the IC regulatory domain, and the USA is
certified in the FCC regulatory domain for operation in the 5 GHz band.
The following countries are certified in the ETSI regulatory domain for operation in the 5 GHz band:
RTS/CTS Medium Reservation
The 802.11 standard supports optional RTS/CTS communication based on packet size. Without RTS/CTS, a sending
radio listens to see if another radio is already using the medium before transmitting a data packet. If the medium is free,
the sending radio transmits its packet. However, there is no guarantee that another radio is not transmitting a packet at
the same time, causing a collision. This typically occurs when there are hidden nodes (clients that can communicate with
the Access Point but are out of range of each other) in very large cells.
–Austria –Greece –Norway
– Belgium – Hungary – Poland
– Czech Republic – Ireland – Portugal
–Cyprus –Italy –Spain
– Denmark – Latvia – Sweden
– Estonia – Lithuania – Switzerland
– Finland – Luxembourg – UK
– France – Malta
– Germany – Netherlands
