Troubleshooting Terminal, Printer and Serial Device Connections - Edition 4 (32022-90030)

Glossary 155
Glossary
Retransmission Timer (T1) so
that no doubt exists about the
link’s state.
topology The physical
arrangement of nodes in a
network. Some common
topologies are bus, star, and ring.
Transmission Control
Protocol TCP. A network
protocol that establishes and
maintains connections between
nodes. TCP regulates the flow of
data, breaks messages into
smaller fragments if necessary
(and reassembles the fragments
at the destination), detects errors,
and retransmits messages if
errors have been detected.
Transpac TCP. The national
public PSN of France.
transparent mode A
data-transfer scheme in which
only a limited number of special
characters retain their meaning
and are acted on by the system.
All other characters are
considered to be data and are
passed through with no control
actions being taken.
transport, network Software
that corresponds to layers 3 and 4
of the OSI network architecture
model. It sends data out over the
communications link, receives
incoming data, and routes
incoming or outgoing data to the
appropriate destination node.
TS8 See HP TS8.
TTUTIL Also known as the
Workstation Configurator. A
program, TTUTIL.PUB.SYS, on
the HP 3000 that is used to create
and modify terminal and printer
type files.
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
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.
V
V24 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