Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)
308 Glossary
Glossary
DDP Direct Distribution Panel; a
distribution panel that serves as
the electrical and physical
interface between a DTC 72MX
mux board (asynchronous
processor board) and up to eight
asynchronous devices for direct
connections. See MDP for modem
connections.;
dedicated printer A printer
that can be used only by one host
on the LAN—the one specified in
the Destination Node Name in
that printer’s configuration
screen.
demodulation The process by
which the information bearing
signal is retrieved from a
modulated carrier wave. The
inverse of modulation.
destination node name In DTS
configuration, it is either 1) the
name of a host that a user can be
connected to by default (if
switching is not enabled for that
user, or if automatic modem
connection is enabled), or 2) the
name of the only host that can
access a dedicated printer.
device class A collection of
devices that have some user
defined relation. Device classes
are assigned through use of the
NMMGR configuration program.
device-dependent
characteristic A file
specification for which
modifications are restricted
because of the type of device on
which the file is opened. For
example, data directed to
terminals must have a blocking
factor of one.
device driver A software
module that controls a specific
type of input/output device.
devicefile A file being input to or
outputfromany peripheral device
except a disk. MPE/iX allows
operations to be performed on the
device itself as if it were a file.
device independence A
characteristic of the operating
system that allows users to
selectively redirect input/output
from a program, session, or job
without regard to the nature of
the device.
device name See PAD name.
Dial ID protocol A proprietary
Hewlett-Packard protocol that
provides security checking and
address exchange for dial links.
dial link A connection made
through public telephone lines.
direct-connect device An
asynchronous device that is
connected directly to a DTC
through an RS-232-C or RS-422
cable, with no intervening
communications equipment. Also
referred to as a “local connection.”
direct connection Aleased line,
private line, or other
non-switched link in a network.