User Manual

SPEEDLAN 9000 Series Installation and Operation User Guide Version 3.03
Glossary-15
Propagation
The transmission of a wave along a given path through a medium.
Protocol
A network protocol is the standard that allows computers to communicate with each other. A protocol defines
how computers identify one another on the network, the form that the data should take in transit, and how
this information is processed once it reaches its final destination. Protocols also define procedures for
handling lost or damaged transmissions or “packets.” IPX (for Novell Netware), TCP/IP (for UNIX, Windows
NT, Windows 95 and 98 and other platforms), DECnet (for networking Digital Equipment Corp. computers),
AppleTalk (for main Macintosh computers), and NetBIOS/NetBEUI (for LAN and Windows NT networks) are
some of today’s most popular networks. Although each network protocol is different, they all share the same
physical cabling. This common method of accessing the physical network allows multiple protocols to
peacefully coexist over the network media, and allows the builder of the network to use common hardware
for a variety of protocols. This concept is known as “protocol independence,” which means that devices that
are compatible at the physical and data link layers allowing the user to run many different protocols over the
same medium.
Pseudo-random Noise code (PN code)
A high rate digital code that mimics random noise-like properties. It is multiplied with a lower rate data
signal in order to achieve spread spectrum transmission signals. The receiver then multiplies the same code
back into the transmission to recover the data signal.
Public Switched Telephone Network (PSTN)
This refers to a worldwide voice telephone network accessible to all those with telephones and access
privileges.
Quadrature Amplitude Modulation (QAM)
A method for modulating a signal by which more than one bit can be sent simultaneously.
Quadrature Phase Shift Keying (QPSK)
Phase-shift keying in which there are four phase states or positions in the time or frequency domains within a
single period.
Radiation
The flow of electromagnetic energy from a transmitter.
Radiation Pattern
An illustration of the energy level radiated by an antenna in every direction.