Troubleshooting Terminal, Printer, and Serial Device Connections - Edition 5 (32022-90058)

Glossary
DTS
Glossary
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DTS Distributed Terminal Subsystem. This consists
of all of the Datacommunications and Terminal
Controllers (DTCs) on a LAN, their LANIC cards
(attached to the host), the LAN cable, and the host
and DTC software that controls all related DTS
hardware.
duplex A transmission method that allows two-way
communication. If both ends of the transmission link
can transmit simultaneously, it is called full duplex.
If only one end can transmit at a time, it is
half-duplex transmission.
E
EEPROM Electrically Erasable Programmable
Read-Only Memory. EEPROM reprogramming is
used to replace a current DTC’s ROM code that
resides on the LAN board. The process is also
referred to as Flash EEPROM reprogramming.
entry priority In a point-to-point network, it is a
ranking that identifies the most desirable route for
data to travel from a given local node to a remote
node.
entry priority In a point-to-point network, it is a
ranking that identifies the most desirable route for
data to travel from a given local node to a remote
node.
environment A session that is established on a
remote node.
escape from data transfer character A
character that allows a user who is connected to a
host system through the DTC, to break that
connection and return to the DTC switching user
interface. The default is
[CTRL]-K
. This character is
used only on networks managed by the OpenView
Windows Workstation.
escape sequence A sequence of characters
beginning with the escape character and followed by
one or more other characters, used to convey control
directives to printers, plotters, or terminals.
Ethernet A Local Area Network system that uses
baseband transmission at 10 Mbps over coaxial cable
and unshielded twisted pair. Ethernet is a
trademark of Xerox Corporation.
event log One of three circular files stored on the
OpenView windows workstation. It contains lists of
events that are reported by the DTCs for which it is
responsible.
F
facility An optional service offered by a packet
switching network’s administration and requested
by the user either at the time of subscription for
network access or at the time a call is made. Also
known as user facility.
facility set A facility set defines the various X.25
connection parameters and X.25 facilities that can
be negotiated for each virtual circuit on a per-call
basis.
fast select An optional packet-switching network
facility by which user data can be transmitted as
part of the control packets that establish and clear a
virtual connection.
FCS Frame Check Sequence. A sequence of bits
generated by X.25 at Level 2 that forms part of the
frame and guarantees the integrity of its frame’s
contents. The FCS is also used by the IEEE 802.3
protocol to check the validity of frames.
file equation An assignment statement used to
associate a file with a specific device or type of device
during execution of a program.
file number A unique number associated with a
file when the file is opened. The file number is
returned in the FOPEN or HPFOPEN call used to
open the file. It can be used to access that file until
the file is closed.
file specification The name and location of a file.
The full specification for a file includes the file name,
group, and account.
file system The part of the operating system that
handles access to input/output devices (including
those connected through the DTC), data blocking,
buffering, data transfers, and deblocking.
Flash EEPROM See EEPROM.
flow control A means of regulating the rate at
which data transfer takes place between devices to
protect against data overruns.