ELECTRONICS
GLOSSARY OF TERMS
Bandwidth: Refers to the capacity or amount of data a specific
technology can send over a given time. It is usually stated in
kilobits per second (kbps) or megabits per second (Mbps). Bits
are used when referring to data transfer rates ( 1 kilobit =
1,000 bits), while bytes are used to specify storage size for
disc drives and other storage media ( 1 kilobyte = 1,024
bytes). There are 8 bits in a byte, which means that at a data
rate of 28. 8 kilobits per second, a maximum of 3. 6 kilobytes
per second are transferred, and this must include the overhead
information required by the transfer protocol. Invariably, the
useful data transfer rate or throughput is less than the maximum
data rate for the type of network in use.
Bluetooth: A wireless technology that allows communication
between Bluetooth-compatible devices. Used for short-range
communications, all Bluetooth devices operate on the 2.4GHz
ISM band with a range of about 30 feet.
Decibel: Abbreviated as dB, db, or DB, the decibel is a
logarithmic expression of the ratio between two signal power
levels. A decibel is 1/10 of a bel, a rarely used unit named
after Alexander Graham Bell, inventor of the telephone.
Because it’s a ratio or comparison between two levels, a
decibel may be positive or negative. When a decibel figure is
shown with a positive value, it refers to a level that is greater
than the base level used for comparison. Conversely, a
negative value indicates a lower value when compared with a
base level.
ERP: Effective radiated power; describes the peak
transmitted power output of the system. Measured in watts,
it includes the transmitter power, the transmission line loss,
and antenna gain (usually as compared to a half-wave
dipole antenna).
ISM band: Industrial, scientific, and medical band; includes
the frequencies between 2. 4 and 2.5GHz that are used by
802.11b/g devices. These frequencies are made available
for unlicensed low-power use and are also used by many
other devices, including portable phones, garage door
openers, and microwave ovens.
Isotropic antenna: A theoretically ideal antenna that radiates
electromagnetic energy with 100 percent efficiency and
equal intensity in all directions. When receiving, it is
considered to be equally sensitive in all directions.
kbps (or kb/sec): An acronym used to express the speed or
rate of a data transmission in kilobits ( 1,000 bits) per
second. If the “b” is capitalized, this refers to kilobytes
per second.
Mbps (or Mb/sec): An acronym used to express the speed of
a data transmission in megabits ( 1 million bits) per second.
If the “b” is capitalized, this refers to megabytes per second.
Wi-fi: An acronym for “wireless fidelity,” the industry term for
a wireless local area network (WLAN). “Wi-fi” is frequently
used interchangeably with the IEEE 802.11b/g network
standard used with many wireless computer networks.
international nonprofit professional organization. The
protocol described by the IEEE 802.11 standard is
commonly used for wireless network communications;
however, there are several variants. The 802.11b and
802.11g versions are almost always used in marina and
home networks. Both of these protocols make use of
the 2.4GHz ISM frequency band, but the new “g”
version is noticeably faster. Virtually all wi-fi adapters
that utilize the 802.11g protocol are also compatible
with networks using the 802.11b standard, but an
older “b” network adapter cannot function on a
network that is communicating with the newer
“g” protocol.
The 2.4GHz ISM band is divided into channels
and is recognized internationally, although the number
of channels may vary slightly. In the United States,
