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position at which the next character to be entered from
the keyboard will be displayed.
data chain. A complete unit of data that originates at a
single LU.
data
link.
(1)
til
The physical means of connecting one
location to another for the purpose of transmitting and
receiving data. (2) (TC97) The assembly of parts of
two data terminal equipments (DTEs) that are
controlled by a link protocol, and that, together with
the interconnecting data circuit, enables data to be
transferred from a data source to a data sink. (3) The
interconnecting data circuit between two or more
equipments operating in accordance with a link
protocol; it does not include the data source and the
data sink. (4) In SNA, synonym for link(3).
data link escape character (DLE). (ISO) A transmission
control character that changes the meaning of a limited
number of contiguously following characters or coded
representations and that is used exclusively to provide
supplementary transmission control characters.
data stream.
(1)
All data transmitted through a data
channel in a single read or write operation. (2) A
continuous stream of data elements being transmitted,
or intended for transmission, in character or binary-digit
form, using a defined format.
data transfer. In telecommunications, the sending of
data from one node to another.
data transfer mode. A set of facilities (including the
macro instructions needed to use them) that enable the
application program to communicate with terminals.
decode.
(1)
(ISO) To convert data by reversing the
effect of some previous encoding. (2) To interpret a
code. (3) Contrast with encode.
detectable. An attribute of a display field; determines
whether the field can be sensed by the selector pen.
display.
(1)
*
(ISO) A visual presentation of data. (2)
(TC95) In word processing, a device for visual
presentation of information on any temporary character
imaging device. (3) (TC97) To present data visually.
display field. A group of consecutive characters (in the
buffer) that starts with an attribute character (defining
the characteristics of the field) and contains one or more
alphanumeric characters. The field continues to, but
does not include, the next attribute character.
duplex. (1)
*
In data communication, pertaining to a
simultaneous two-way independent transmission in both
directions. Synonymous with full duplex.
*
EBCDIC. Extended binary-coded decimal
interchange code. A coded character set consisting of
8-bit coded characters.
echo. A feature that makes a receiving device send
back the characters it receives. Echo is controlled at
three points within the data communications system:
• The user's terminal
• The dataline ECHO parameter
• The answering data resource.
If all three setting do not complement each other, the
result is either a blank screen or double images when the
user types at the terminal.
EEPROM.
... Electrically erasable programmable
read-only memory located in the base unit of the 3708.
EIA 131C. The EIA standard describing the electrical,
mechanical, and functional interface between data
terminal equipment and data communication equipment
using serial binary data. The EIA 232C interface is the
most common interface for attaching data
communications devices. Cable length cannot exceed 50
feet.
EIA 411A. The EIA standard for serial data
transmission. EIA 422A interface allows devices to be
direct attached at greater distances, up to 4000 feet.
The EIA 422A interface is only supported for
asynchronous device attachment.
emulate.
(1)
To imitate one system with another,
primarily by hardware, so that the imitating system
accepts the same data, executes the same computer
programs, and achieves the same results as the imitated
computer system. (2) The use of programming
techniques and special machine features to permit a
computing system to execute programs written for
another system.
encode. (1)
*
(ISO) To convert data by the use of a
code or a coded character set in such a manner that
reconversion to the original form is possible. Encode is
sometimes loosely used when complete reconversion is
not possible. (2)
*
(ISO) Contrast with decode.
EPROM.
*
Erasable programmable read-only memory
located in the cartridge of the 3708.
Erase AU Unprotected (EAU) command. A command
that clears all unprotected fields to nulls, resets modified
data tags in all unprotected fields, unlocks the keyboard,
resets the attention identifier, and repositions the cursor
to the first character of the first unprotected field.
Erase Unprotected to Address (EUA) order. An order
that erases all unprotected positions (inserts nulls) from
the current buffer address up to, but not including, the
specified stop address.
ESC character. See data link escape character.
Glossary
X-7
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