IBM 3164 ASCII Manual page 222

local mode. In a telecommunication system, the
operation of a terminal without interaction with the
host program.
modem(modulator-demodulator). A device that
modulates and demodulates signals transmitted over
telecommunication facilities.
modified data tag (M DT). A bit in the attribute
character of a display field that, when set, causes that
field to be transferred to the channel during a
read-modified operation. The MDT may be set by a
keyboard input to the field, or by program control. It
may be reset by program control or by the erase input
(Er Inp) key.
nonswitched line. A telecommunication line on
which connections do not have to be established by
dialing.
null character (NUL). A control character that is
used to accomplish media-fill or time-fill, and that
may be inserted into or removed from a sequence of
characters without affecting the meaning of the
sequence; however, the control of equipment or the
format may be affected by this character.
null suppression. The by-passing of all null
characters to reduce the amount of data to be
transferred.
operator information area. For the IBM 3164,
the 25th row of data on the display surface in which
the operator is supplied information concerning
system status.
parity check. (1) A redundancy check that uses a
parity bit. (2) For the IBM 3164, occurs when 3164
circuitry detects one or more characters with bad
parity in a buffer.
permanent-request-to send (PRTS). A line
control used on a duplex facility for a simultaneous
data transmission. The request-to-send (RTS) signal
goes on at power-on and stays on until the terminal is
powered-off.
protected field. On a display device, a display field
in which the user cannot enter, modify, or erase data.
Data in this field is displayed in blue instead of green
in Default Color mode.
remote attachment. The attachment of a terminal
or other similar device to a host computer by means of
a data link; for example, a modem.
reverse video. A form of highlighting a character,
field, or cursor by reversing the color of the character,
field, or cursor with its background; for example,
changing a green character on a black background to
a black character on a green background.
scro"ing. In computer graphics, moving, vertically
or horizontally, a display image in a manner such that
new data appears at one edge as old data disappears
at the opposite edge.
start-stop transmission. Asynchronous
transmission such that a group of signals representing
a character is preceded by a start element and
followed by a stop element.
switched line. A telecommunication line in which
the connection is established by dialing. Contrast
with nonswitched line.
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