User Manual

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setting of the
Transmission Rate
control is fixed because of the
Network Mode
setting, it is
shown in gray characters and the control is disabled.
When the
Network Mode
control is set to
802.11 Ad-hoc
, the
Transmission Rate
control offers
five settings:
Auto
,
1 Mbps
,
2 Mbps
,
5.5 Mbps
, and
11 Mbps
.
Using a fixed, high speed throughout a network can improve security by reducing the effective
range. Fixed, low speeds may be necessary for interoperation with some pre-802.11b devices.
The
Auto
setting lets the adapter adjust communication speed according to signal quality; this
setting thus offers the best combination of throughput, range, and resistance to interference.
7.2.4 Network Mode
The
Network Mode
control is a drop-down list that offers three settings:
802.11 Ad-hoc
,
Infrastructure
, and
High Speed Ad-hoc
. You can learn from the
Settings
panel’s
Site Survey
section if a network is in ad-hoc or infrastructure mode; the network installer or operator can tell
you if an ad-hoc network is high-speed (22 Mpbs). You must choose the setting that agrees with
the actual operating mode of the network. High-speed ad-hoc mode can only be used by devices
in the same product family as your adapter.
7.2.5 Channel
Depending on which part of the world you are in, there can be up to 14 “channels” in the radio
frequency band used for wireless networking (2.4 to 2.4835 GHz in most countries). A channel
consists of 23 exact frequencies spaced 1 MHz apart for a total spread of 22 MHz. Such spreading
is required by regulatory agencies to reduce interference among devices operating in this band.
On an infrastructure network, each access point (AP) is set to use a fixed channel, and stations
automatically detect the channel used by the AP that provides the best signal quality. The
Channel
control is therefore disabled when the
Network Mode
control is set to
Infrastructure
.
An ad-hoc network operates on a fixed channel that will be shown in the
Settings
panel’s
Site
Survey
section. To join a given ad-hoc network, you must select the correct channel from the
Channel
control’s drop-down list. The settings offered in the list depend on the regulations of the
country in which the adapter was purchased.
APs with overlapping coverage areas, or different ad-hoc networks operating in the same area,
should use channel settings that are at least four, and preferably five channels apart (for example,
1, 6, and 11) to avoid interference and obtain the best possible performance.
7.2.6 Power Saving Mode
The
Power Saving Mode
control is a drop-down list that offers three settings:
Continuous
Access Mode
,
Maximum Power Save
, and
Fast Power Save
.
In Continuous Access mode, your adapter’s receiver is always on.
Maximum Power Save mode is a “doze” mode in which the adapter turns its receiver off but
“wakes up” at fixed intervals to see if any communications are waiting for it. Before entering this
mode, it tells the AP (or, on an ad-hoc network, the current coordinating station) that it is going to
do so. The AP (or coordinating station) will “buffer” (temporarily store) communications