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OEM User’s Manual
37
Many countries specify the channel range and power limits for Wi-Fi devices operated
within their borders, and these limits are set automatically in the RCM4400W in firmware
according to the country or region. For example, only channels 1–11 are authorized for use
in the United States or Canada, and so channels 12 and 13 are disabled. See Section 6.2.4.1
for additional information and sample programs demonstrating how to configure an end
device to meet the regulatory channel range and power limit requirements. Table 5 pro-
vides additional information on which channels are allowed in selected countries.
Any
attempt to operate a device outside the allowed channel range or power limits will void
your regulatory approval to operate the device in that country.
U21 and U23 are bandpass filters to reduce the transmit and receive sideband noise levels.
The same antenna is used to transmit and receive the 802.11b RF signal. An antenna
switch isolates the high-power RF Tx signal path from the RF Rx signal path. The antenna
switch works by alternately connecting the antennas to either the UW2453 Tx output or to
the UW2453 Rx input. In order to support this antenna-sharing scheme, the RCM4400W
module operates the radio in a half-duplex mode so that receive and transmit operations
never occur at the same time The chip at U22 switches the receive/transmit functionality
between the outputs at J3 and J4 (not stuffed) so that J3 is transmitting while J4 would be
receiving and vice versa. Dynamic C does not support a J4 output.
Table 4. Wi-Fi Channel Allocations
Channel
Center Frequency
(GHz)
Frequency Spread
(GHz)
1
2.412
2.401–2.423
2
2.417
2.406–2.428
3
2.422
2.411–2.433
4
2.427
2.416–2.438
5
2.432
2.421–2.443
6
2.437
2.426–2.448
7
2.442
2.431–2.453
8
2.447
2.436–2.458
9
2.452
2.441–2.463
10
2.457
2.446–2.468
11
2.462
2.451–2.473
12
*
2.467
2.456–2.478
13
*
2.472
2.461–2.483
14
(not used)
2.484
2.473–2.495
* These channels are disabled for units delivered for sale in the United
States and Canada.
Summary of Contents for RabbitCore RCM4400W
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