Configuring Systems for Terminals, Printers, and Other Serial Devices (32022-90057)

Glossary
X.25 iX System Access
Glossary
263
Tymnet A proprietary public data network in the
USA.
typeahead A facility that allows terminal users to
enter data before a read is actually posted to the
terminal.
U
UPS See uninterruptible power supply.
unacknowledged frame number (K) The
number of frames that can be transmitted without
receiving an acknowledgment from the destination
address. When this number (K) frame is reached, the
same K frames are retransmitted.
unedited mode See transparent mode.
uninterruptible power supply A hardware
device that protects equipment from power failures
and contains an internal storage battery to supply
reserve power.
V
V.24 The CCITT recommendation that defines the
function of the interchange circuits between a DTE
and a DCE.
validation The process of ascertaining whether the
network transport configuration file has been
correctly configured. This is accomplished by using
the NMMGR Validate Configuration File screen.
VAN Value-Added Network. A data communication
network that uses and pays for facilities belonging to
another carrier. The value-added package is then
sold to a user.
VC See virtual circuit.
virtual circuit A logical association between two
physically separate DTEs.
Virtual Terminal A network service that allows a
user to establish interactive sessions on a node.
VPLUS Software used to generate screens such as
those displayed by NMMGR.
V-Series (V.##) CCITT A set of CCITT
recommendations related to data communication
over a voice-grade telephone network.
VT See Virtual Terminal.
W
WAN Wide Area Network. A data communications
network of unlimited size, used for connecting
localities, cities, and countries.
Workstation Configurator A utility available on
MPE/iX systems, TTUTIL.PUB.SYS, that allows users
to create customized terminal and printer types by
entering data through a series of VPLUS screens.
X
X.3 The protocol that defines which user facilities
should be internationally available from a packet
assembler/disassembler (PAD) when this is offered
by a public data network.
X.21 The protocol that defines the physical interface
between a DTE and a DCE of a public data network
where the access to the network is made over
synchronous digital lines.
X.25 The protocol that defines the interface between
a DTE and a DCE for packet-mode operation on a
Public Data Network (PDN).
X.25 address The X.25 address provided by the
network administration if you are connected to a
public data network (PDN).
X.25 address key An X.25 address key is a label
that maps a node’s IP address to its X.25 address
and its associated X.25 parameters. You have a
combined maximum of 1024 X.25 address keys in
the SVC and PVC path tables.
X.25 LUG address X.25 address of a node
belonging to a LUG.
X.25 iX System Access The software that works in
conjunction with the DTC/X.25 Network Access
software to provide MPE/ iX access to X.25. The
software resides on an HP 3000 host and is
configured through use of NMMGR. To configure
access to an X.25 network, you must configure two
software components: the X.25 iX System Access and