Configuring and Managing Host-Based X.25 Links - Edition 6 (36939-90057)

Glossary
baud
Glossary
220220
baud Measure of the speed at which information
travels between devices, most commonly used in
reference to terminal speed settings. Baud
represents signal events per second. When one bit
represents each signal change, baud is the same as
“bits per second”.
binary mode Data transfer scheme in which no
special character processing is performed. All
characters are considered to be data and are passed
through with no control actions being taken.
bit Binary digit. A unit of information that
designates one of two possible states, which are
represented by either 1 or 0.
block mode Terminal processing mode in which
groups, or “blocks,” of data are transmitted all at
once.
BNC T-Connector Connector used to connect a
computer or a component such as a DTC to the LAN
in a ThinLAN configuration.
boundary See network boundary.
bps Bits per second. The number of bits passing a
point per second.
broadcast Communication method of sending a
message to all devices on a link simultaneously.
byte A sequence of eight consecutive bits operated
on as a unit.
call In X.25, a call is an attempt to set up
communication between two DTEs using a virtual
circuit. Also known as a virtual call.
call collision A conflict that occurs at a DTE/DCE
interface when there is a simultaneous attempt by
the DTE and DCE to set up a call using the same
logical channel identifier.
called address When a node sends out a call
request packet, the packet contains the address of
the destination node. The address of the destination
node is the called address.
calling address When a node receives an incoming
call packet, the packet contains the address of the
sending node. The address of the sending node is the
calling address.
carrier A continuous wave that is modulated by an
information bearing signal.
catenet See internetwork.
CCITT Consultative Committee for International
Telephony and Telegraphy. An international
organization of communication carriers, especially
government telephone monopolies, responsible for
developing telecommunication standards by making
recommendations. No carrier is required to adhere to
a CCITT recommendation, although most do so in
their own interest.
CIB The channel input/output bus in the backplane
of an HP 3000.
circuit-switching network A type of data
communications network wherein a physical and
exclusive link is maintained between two
communicating devices for the call duration. An
all-digital, circuit-switching network is often
referred to as an X.21 network.
closed user group An X.25 user facility that allows
communication to and from a pre-specified group of
users and no one else.
compatibility mode Processing mode on HP 3000
Series 900 computers that allows applications
written for MPE V/E-based systems to be ported and
run without changes or recompilation.
computer network A group of computer systems
connected in such a way that they can exchange
information and share resources.
configuration 1) The way in which computer
equipment is physically interconnected and set up to
operate as a system.
2) The layout of the computer system, including the
MPE table, memory, and buffer sizes, that tells
which peripheral devices are (or can be) connected to
the computer and how they can be accessed.
3) The process of defining the characteristics of a
network in software. For MPE/iX-based computers,
the operating systems are configured through use of
the SYSGEN utility. Next, the datacommunications
and terminal subsystem (DTS) link is configured by
using NMMGR (running on the host) and may, in
addition, be configured using the OpenView DTC
Manager software (running on the OpenView