IBM 8285 Nways, Installation And User Manual

Page: 246 / 265

data transmission. The conveying of data from one
place for reception elsewhere by telecommunication
means. (I)
dB. Decibel.
dBm. Decibels based on 1 milliwatt.
dc. Direct current.
decibel (dB). (1) One tenth of a bel. (2) A unit that
expresses the ratio of two power levels on a logarithmic
scale. (3) A unit for measuring relative power. The
number of decibels is 10 times the logarithm (base 10)
of the ratio of the measured power levels; if the
measured levels are voltages (across the same or equal
resistance), the number of decibels is 20 times the log of
the ratio.
decibels based on 1 milliwatt (dBm). A unit of
absolute power measurement that is scaled such that 0
dBm equals 1 milliwatt.
default. Pertaining to an attribute, condition, value, or
option that is assumed when none is explicitly
specified. (I)
destination. Any point or location, such as a node,
station, or particular terminal, to which information is to
be sent.
device. (1) A mechanical, electrical, or electronic
contrivance with a specific purpose. (2) An input/output
unit such as a terminal, display, or printer.
diagnostics. Modules or tests used by computer users
and service personnel to diagnose hardware problems.
Disk Operating System (DOS). An operating system
for computer systems that use disks and diskettes for
auxiliary storage of programs and data.
DMM. Distributed Management Module.
DOS. Disk operating system.
dump. (1) To record, at a particular instant, the
contents of all or part of one storage device in another
storage device. Dumping is usually for the purpose of
debugging. (T)
(2) Data that has been dumped. (T)
(3) To copy data in a readable format from main or
auxiliary storage onto an external medium such as tape,
diskette, or printer. (4) To copy the contents of all or
part of virtual storage for the purpose of collecting error
information.
E
EIA. Electronic Industries Association.
EEPROM. Electrically erasable programmable
read-only memory.
electrically erasable programmable read-only
memory (EEPROM). A PROM that can be erased by a
special process and reused. (T)
Electronic Industries Association (EIA). An
organization of electronics manufacturers that advances
the technological growth of the industry, represents the
views of its members, and develops industry standards.
equipment rack. Synonym for rack.
Ethernet. A local area network that allows multiple
stations to access the transmission medium at will
without prior coordination, avoids contention by using
carrier sense and deference, and resolves contention by
using collision detection and delayed retransmission.
F
F. Fahrenheit.
FCC. Federal Communications Commission (USA).
FDDI. Fiber Distributed Data Interface.
fiber. Synonym for optical fiber.
fiber budget. The optical power loss as a result of the
number of connections in the optical fiber link subtracted
from the working budget. The loss as a result of
connections includes the connector loss and the splice
loss. The fiber budget is expressed in decibels.
Fiber Distributed Data Interface (FDDI). A
high-performance, general-purpose, multi-station
network. It uses token-ring architecture with optical fiber
as the transmission medium over distances of several
kilometers.
fiber optic cable. Synonym for optical cable.
fiber optics. The technology whereby optical signals
from light-generating transmitters are propagated
through optical fiber waveguides to light-detecting
receivers.
218
IBM 8285 Nways ATM Workgroup Switch: Installation and User’s Guide