Multitech MT5634HD16 User Manual page 66

MT5634HD8/16 User Guide
Bus: A common channel between hardware devices either
internally between components in a computer, or externally,
between stations in a communications network.
Byte: The unit of information a computer can handle at one
time. The most common understanding is that a byte consist
of 8 binary digits (bits), because that's what computers (PCs)
can handle. A byte holds the equivalent of a single character,
such as the letter "A".
C
CAD (computer aided design - pronounced "kad"): A
computerized system used to design products. CAD systems
are high speed workstations or PCs that use CAD software
and input devices, such as graphic tables and scanners.
Callback security: A security feature available in some
intelligent modems that stores phone numbers. When
activated, the user calling the secured modem must furnish a
recognized password, and then provide a code that
corresponds to one of the stored phone numbers. When
these security measures are met, the secured modem hangs
up on the caller and dials the appropriate number to
establish a data communications link.
Capacitor: An electronic device that stores an electrical
charge. It comes in varying sizes for use in anything from
power supplies to the tiny cells in dynamic RAM chips.
When the device is powered down, it's capacitors lose their
charge.
Carrier signal: An analog signal with known frequency,
amplitude and phase characteristics used as a transport
facility for useful information. By knowing the original
characteristics, a receiver can interpret any changes as
modulations, and thereby recover the information.
Character set: One of a number of coding schemes which
uses binary digits to represent characters, numbers,
punctuation, and/or control characters. Common character
sets are ASCII, ANSI, and EBCDIC.
Checksum: A control field found in synchronous data
packets which contain the results of the error control
algorithm used.
Chip: Also called integrated circuits (IC), they are squares or
rectangles that contain from a few dozen to a few million
electronic components.
CHKDSK (pronounced "check disk"): An external DOS
command that reports free memory and disk space.
CHKDSK must be run directly from DOS or within a batch
file.
Circuit: Any closed path through which electrical current
can flow.
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Circuit-switched Network: A technology used by the PSTN
that allocates a pair of conductors for the exclusive use of
one communication path. Circuit switching allows multiple
conversations on one talk path only if the end-users
multiplex the signals prior to transmission.
Circuit switching: The temporary connection of two or
more communications channels using a fixed, non-shareable
path through the network. Users have full use of the circuit
until the connection is terminated.
Clipboard: An electronic holding place for the most recent
cur or copy made from a document. Whatever is on the
clipboard can be pasted into the current document. Only one
item may be on the clipboard at a time. When new copy is
sent to the clipboard the existing copy is eliminated. When
you shut down your computer, whatever is on the clipboard
is lost.
Clock: A timing signal generated by an oscillating circuit
which is used to synchronize data transmissions.
Command: An instruction that tells a computer to begin,
continue, or end a specific operation.
Command mode: One of two states of an intelligent
(programmable) device. The mode in which commands can
be issued to alter operating parameters.
Communications Server: Also known as the Async
Gateway, it is a PC equipped with the appropriate hardware
and software package so it can function as a gateway
between a LAN and its modems or host connections.
COMx Port: A serial communications port on a PC.
CONFIG.SYS file (pronounced "config dot sis"): A text file
that contains configuration commands used when you start
your computer. Commands in the CONFIG.SYS file enable or
disable system features, set limits or resources, and extend
the operating system's purpose by loading device drivers.
Cooked data: A term used in UNIX communications to
identify the UNIX command-line data transmitted. This type
of data is noted for a reduction in effective throughput
because it has to be processed, or "cooked" prior to
transmission. Compare with raw data.
CPU (central processing unit): The computing part of the
computer. It is made up of the control unit and the ALU
(arithmetic logic unit). The CPU, clock and main memory
make up a computer. When you turn on your computer, an
electrical signal follows a permanently programmed path to
the CPU to clear the leftover data from the chips' internal
memory registers.
CRC (Cyclic Redundancy Check): A field used in
packetized data that contains two 8-bit BCCs (Block Check
Characters) as the binary result of an algorithm performed
CommPlete Communications Server