Cabletron Systems 3Com manual Radio Basics, PowerBASE-T, Wireless clients and APs

14CHAPTER 1: OVERVIEW OF DIGITAL WIRELESS NETWORKING

	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.