Cabletron Systems 3Com Manual De Usuario

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14
C
HAPTER
 1: O
VERVIEW
 
OF
 D
IGITAL
 W
IRELESS
 N
ETWORKING
For details concerning the installation of your PowerBASE-T, see “Using the 
PowerBASE-T”.
Radio Basics
AirConnect devices use radio signals to transmit and receive data without wires. 
You can communicate with the network by establishing radio links between 
wireless clients and APs.
AirConnect uses Quadative Phase Shift layered modulation (QPSK) to transmit 
digital data from one device to another. Using QPSK, a radio signal begins with a 
carrier signal that provides the base or center frequency. The digital data signal is 
superimposed on the carrier signal in process called “modulation.” The radio 
signal then travels through the air as electromagnetic waves. A receiving antenna 
in the path of the waves absorbs them as electrical signals. The receiving device 
“demodulates” the signal by removing the carrier signal. This demodulation 
results in the original digital data.
AirConnect uses its environment (the air and certain other objects) as the 
transmission medium. AirConnect radio devices transmit in the 2.4-2.5 GHz 
frequency range, a license-free range throughout most of the world. The actual 
range your AirConnect network operates at is country-dependent.