Instruction Sheet

Frequencies: Strike a piano key and you generate a tone. Pick up the tone with a microphone
and your tone turns in to a “vibrating” or “cycling” electronic signal. The rate of vibration depends
on the key struck. In electronics we refer to this rate of vibration as the number of “cycles per
second.” The formal term for this value is Hertz. As we move up in rate, such as in the Broadcast
Band, we can use Kilohertz (KHz) to represent 1,000 Hz, or Megahertz (MHz) to represent
1,000,000 Hz. Continuing much further upward, we finally reach 1,000,000,000 Hz, which we can
fortunately shorten to a Gigahertz (GHz). These frequencies are the home of both 802.11a (5
GHz) and 802.11b (2.4 GHz).
I
Independent Basic Service Set Identifier (IBSSID): Used to identify a wireless network
configured to allow each wireless client to communicate directly with each other without an
access point.
Independent Network: A network that provides (usually temporarily) peer-to-peer connectivity
without relying on a complete network infrastructure.
Infrastructure Mode: A wireless network centered around an access point. In this environment,
the access point not only provides communication with the wired network but also mediates
wireless network traffic in the immediate neighborhood.
Institute of Electrical and Electronics Engineers (IEEE): An organization involved in setting
computing and communications standards.
ISM Bands: A series of frequency bands, set aside by the FCC for Industrial, Scientific and
Medical applications. Users of these bands operate equipment on a shared basis, meaning that
they must expect, and accept interference from other legal users. Products manufactured for ISM
Band use must be approved by the FCC, but the user does not have to be licensed. In addition to
WLAN, ISM bands support cordless phones, microwave ovens, baby monitors, toys, ham radio
transceivers, and other wireless services.
K
Kerberos: An authentication system enabling protected communication over an open network
using a unique key called a ticket.
M
Media Access Control (MAC) Address: A hardwired address applied at the factory. It uniquely
identifies network hardware, such as a wireless PC Card, on a LAN or WAN.
Microcell: A bounded physical space in which a number of wireless devices can communicate.
Because it is possible to have overlapping cells as well as isolated cells, the boundaries of the
cell are established by some rule or convention.
Microwave: Technically, the term describes any frequency above 1.0 GHz. Unfortunately the
advertising industry has contorted this meaning considerably. In our discussion we will stick to the
technical definition.
Multipath: The signal variation caused when radio signals take multiple paths from transmitter to
receiver.