Multitech CommPlete MT5634HD8, Руководство пользователя, Страница: 86 / 99

MT5634HD8 User Guide
80 CommPlete Communications Server
LRC (Longitudinal Redundancy Check) : An
error checking method that generates a parity
bit from the specified string of bits on a
longitudinal track. In a row and column format
such as on magnetic tape, LRC is often used
with VRC, which creates a parity bit for each
character.
M
Macro : A series of keystrokes, commands,
and/or menu selections that have been recorded
and assigned a key or key combination. When
those keys are pressed, the macro is executed
from beginning to end.
Magnetic Disk : A non-volatile computer
storage device that uses one or more magnetic-
coated disk platters that can be recorded over
and over again. Hard disks, minifloppies (5-
1/4”) and microfloppies (3-1/2”) are examples
of magnetic disks.
Mainframe : A large, powerful computer used to
centralize a data processing environment. It has
hundreds of gigabytes of storage space. It uses a
frond end processor to connect directly to the
communications channels that interconnect
terminals and computers.
Megabyte : One million bytes, when describing
a data rate. 1M of disk space may actually
mean 1,048,576 bytes.
Mid-range computer : A term coined by IBM,
referring to any of their Advanced Business
Systems computers. This product line was
originally called their mini-computers, but as
the number of supported users approached
mainframe capabilities, the term “mid-range”
caught on.
MI/MIC (mode indicate/mode indicate
common interface)
: A user definable feature
that defines various combinations of edge or
level detection in Originate or Answer mode,
with the Ring Indicator (RI) pulse enabled or
disabled.
Mnemonics : A term assigned to a complex
idea, value, or list of information which is
found to be representative of that information.
Computer commands are almost entirely
mnemonics. Mnemonics are used as memory aids
for people.
MNP (Microcom Networking Protocol) : A
family of communications protocols from
Microcom that have become de facto standards
for error correction and data compression.
MNP Class 3&4 : The de facto error correction
standard from Microcom.
MNP Class 5 : The most widely used data
compression scheme before V.42bis took hold.
MNP5 offers “2-to-1” data compression.
MNP Class 7 : MNP’s “3-to-1” data compression
scheme. MNP7 never became a de facto
standard because of V.42bis “4-to-1”
compression.
Modem : A communications device that enables
a computer to transmit information over a
telephone line. It converts the computer’s
digital signals into analog signals to send over
a telephone line and converts them back to
digital signals at the receiving end. Modems
can be internal and fit into an expansion slot, or
external and connect to a serial port.
Modulation : The process of encoding
information from one signal (called the source)
into another (called the carrier) by modifying
some characteristic(s) of the carrier. It is often
used in telecommunications when one type of
signal must be converted for transmission over
an otherwise incompatible medium.
Multiplexer (mux) : A device that merges
several signals into one composite signal for
transmission over a single medium or channel. A
de-multiplexer (usually built into a mux)
reverses the process at the receiving end.
N
NAK (Negative Acknowledgment) :
Communications code used to indicate that a
message was not properly received, or that a
terminal does not wish to transmit. Contrast
with ACK.
Network : A group of computers connected by
cables or other means and using software that
enables them to share equipment, such as
printers and disk drives to exchange
information.
NIC (Network Interface Card - pronounced
“nick”)
: A printed circuit board that provides
the physical and electrical connection between
a PC and a network device (like a file server)
via a network media (like Arcnet UTP).