| Half Duplex
(HDX) |
-
Alternating transmissions; each station can
either transmit or receive, not both simultaneously.
-
Describes the condition when a terminal displays
its own transmissions instead of a remote end echo.
-
A configuration option in some modems allowing
local character echo.
|
| Hand Held Terminal
(HHT) |
An LXE terminal that was designed for the users to
hold in their hands, usually with a self contained battery. However, some hand
held terminals may be bolted down or connected to an outside battery supply.
See also Vehicle Mounted Terminal.
|
| handshaking |
The signal between two devices indicating that the
transfer of data is conveyed and received successfully.
|
| hard disk |
A storage device composed of a rigid platter or
platters used for long term data storage. Hard disks hold much more information
than diskettes, and are not usually user removable. By default, the hard disk
is referred to as drive C. |
| hard disk drive
(HDD) |
The mechanism designed to read and write data and
programs on a hard disk.
|
| hardware (H/W) |
The physical, electronic and mechanical components
of a computer system, including devices such as a display, disk drive, printer,
mouse or processor.
|
| hertz (Hz) |
International standard unit of frequency. A unit of
frequency that is equal to one cycle per second. Replaces the identical older
"cycles-per-second." |
| hexadecimal (HEX) |
The base 16 numbering system used to represent
binary numbers by programmers. See also binary. |
| High-level Data Link Control
(HDLC) |
A bit oriented data link control that is
functionally similar to Advanced Data Communications Control Procedures (ADCCP). |
| High Memory Area
(HMA) |
The first 64KB of extended memory.
|
| host address |
An address displayed by the network management
workstation that identifies the terminal to the host.
|
| host application |
An application program that resides in the host
computer. For example, a program that facilitates cycle counting for inventory
purposes. |
| host computer |
-
An asynchronous or synchronous computer system
that executes application programs and maintains data bases.
-
A computer that executes application programs,
allowing it to communicate with the network controllers, RFUs, and terminals.
|
| host link |
A communication link between the network controller
and host computer. |
| Host Number |
The device host identifier, a unique alphanumeric
ID. Each LXE device can interact with only one of at least 5 hosts -- LDS,
TELNET, LAT, and IBM's 3270 and 5250.
|
| host response time |
The measure of time that elapses between the
network controller transmitting a message to the host and receiving an
acknowledgment for that message. |
| hot key |
A key combination that is a shortcut to
accomplishing a task. For example, <Ctrl> <9> is the hot key
operation that allows the user to toggle the 2280 terminal between two
different emulations.
|
