Table of Contents
Advertisement
OPERATION
4023
Users
Roll-Up
Direct
Entry
is
the only
mode
in
which
roll-up
occurs. Roll-up
occurs
when
a line
feed
from
the
keyboard
or
computer
tries
to position the cursor
past
the
bottom
line
on
the
display.
Note
the
effect
of
roll-up
by
switching to
Dl
RECT
and
typing
a
few
lines
of text
at
the top
and
bottom
of
the
display.
Position
the cursor to the
bottom
line,
then
press
the
LF
(line
feed)
Key.
Note
that
all
lines
of displayed data
move
up one
line,
leaving
a
new
line at
the
bottom:
note
that the
top
line
is
lost.
Switch back
to
BUFFER.
Buffer
Mode
In
Buffer
communications,
the
keyboard
entries are
first
stored
in
the
Terminal
memory,
displayed,
and
edited
by
the operator before being
transmitted to the
computer.
Buffered
communications
can be with
or
without
a
formatted
display.
Non-formatted
displays are
used
for
operations
such
as
programming. Formatted
displays (Buffer
Form
Fill-Out
Entry)
are
used
for
those data entry operations
requiring
a
form-type arrangement
of
data.
Buffer
Operation
Fig.
1-15
shows
a
partial
display
illustration
of
a
typical
Buffer
Transmission (non-formatted
display)
sequence.
The
first
line
is
transmitted
to
the
computer
when
the operator presses the
SEND/ENTER
key,
initiating
an
Enter sequence.
Pressing
this
key
causes
a
rectangular
marker about
cursor
size
to
be displayed
at
the cursor
location.
This
display
marker
is
called a
Message
Separator,
and
is
used to bracket information transmitted
to
the
computer.
If
no
preceding
Message Separator
is
displayed,
data
transmission occurs
from
the
home
position to
the
Message Separator caused
by
pressing the
SEND-ENTER
key.
As
the data
is
being transmitted, the
KEYBOARD
LOCK
indicator
becomes
lighted
as
an
indication
that
keyboard
entry
is
inhibited
until
the transmission
sequence
is
finished.
Also,
if
a
key
is
pressed during
a
buffer transmission sequence, the
bell will ring.
If
the
WAIT
indicator
is
on,
this
is
a signal
that the transmission
sequence
cannot
begin
until
the
WAIT
indication ends.
Visual indications that
an
On
Line buffer
sequence
has
been
initiated
are:
1.
Message Separator
stores at
the cursor location
when
ENTER
key
is
pressed.
2.
Cursor
moves
back through
text seeking the
home
position or
a
previously stored
Message
Separator.
1-24
®
Advertisement
Table of Contents
