IBM 3174 Reference Manual page 208

Glossary
The terms In this glossary are defined here as they apply to the 3270 Information Display
System.
active iogicai terminal (LT). in MLT, the currently
displayed logical terminal. Synonymous with
foreground logical terminal. Contrast with background
logical terminal.
adapter. A general term for a device that provides
some transitional function between two or more
devices.
AEA port. A communication connector on the
Asynchronous Emulation Adapter (AEA).
American National Standard Code for information
interchange (ASCII). A standard code, using a coded
character set consisting of 7-blt coded characters (8
bits Including parity check), used for Information
Interchange among data processing systems, data
communication systems, and associated equipment.
The ASCII set consists of control characters and
graphic characters.
application. The use to which an Information
processing system Is put, for example, a payroll
application, an airline reservation application, or a
network application.
application program. (1) A program written for or by a
user that applies to the user's work, such as a program
that does Inventory control or payroll. (2) A program
used to connect and communicate with stations In a
network, enabling users to perform application-oriented
activities.
ASCII emulation. The ability of a 3270 display station
or printer to communicate with an ASCII host using the
DEC VT100, DEC VT200, IBM 3101 or the D210 data
stream.
ASCII pass-through. The transmission of unmodified
data between ASCII display stations or printers and an
ASCII host or public data network.
ASCII pass-through mode. For an ASCII device
attached to a 3174, a mode of operation In which the
device communicates with an ASCII host.
asynchronous. (1) Without regular time relationship;
unexpected or unpredictable with respect to the
execution of program Instructions. (2) In asynchronous
data transmissions, data characters may be sent or
' Copyright IBM Corp. 1987, 1930
received at any time; no modem clocking Is used to
establish bit timing.
Asynchronous Emulation Adapter (AEA). In the 3174
Establishment Controller, an adapter that enables an
ASCII terminal to communicate with a 3270 host using
the 3270 data stream, an ASCII terminal to
communicate with an ASCII host through the 3174, and
a 3270 terminal to communicate with an ASCII host
using data streams, such as the DEC VT100 data
stream or the IBM 3101 data stream.
attach. To connect a device logically to a 3174
adapter, so that It can communicate over the network.
attention (ATTN). An occurrence external to an
operation that could cause an Interruption of the
operation.
attention field. In the 3270 Information Display
System, a detectable field In which the designator
character Is a null, a space, or an ampersand.
attention identifier (AID). (1) A code In the Inbound
3270 data stream that Identifies the source or type of
data that follows. (2) A character In a data stream
Indicating that the user has pressed a key, such as
Enter, that requests an action by the system.
attribute. (1) A characteristic. (2) A terminal display
language or transformation definition language (TDL)
keyword that specifies a particular quality for the TDL
object with which It Is associated.
auto-answer. See automatic answering.
autobaud. In the 3174 AEA feature, the process of
determining the line speed and parity settings of a
connecting display station from a specific sequence of
characters (OR . CR) entered from the keyboard. ASCII
hosts may also support automatic speed and parity
detection, but the character sequence they require may
differ.
auto-call. See automatic calling.
automatic answering. (1) Answering In which the
called data terminal equipment (DTE) automatically
responds to the calling signal.
Note: The call may be established whether or not the
called DTE Is attended.
(2) A machine feature that permits a station to respond
without operator action to a call It receives over a
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