Heathkit H9 - Control Characters and Hold Screen

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@
CONTROT
CHARACTERS
The Terminal
generates
all 32 ASCII
control
charac-
ters from the keyboard.
Normally these
characters do
not write into RAM,
nor are they
displayed
on
the
screen. Exceptions
are
outlined in the description
of
the
plot
mode. The
Terminal recognizes
only
four
of
the control
characters. It will recognize
these from
the
keyboard
or from the
parallel
or serial input
ports.
The
four characters
are:
Line Feed
(LF
or CTRL
])
-
This
character du-
plicates
the LINE FEED key.
Carriage Return
(CR
or CTRL M)
-
This
charac-
ter duplicates
the RETURN
key.
Back
Space
(BS
or CTRL H)
-
This
character
moves the cursor to the left
one character
posi-
tion without disturbing the
character being dis-
played.
Bell
(Bel
or
CTRL
G)
-
This
character causes the
Terminal to
sound a short audible tone
through
an internal speaker. Pictorial 1-3
shows the con-
trol and normal characters thattheTerminal
can
generate.
HOLD
SCREEN
If the screen has been
filled,
and a scroll
function
should occur,
but can't
because the SCROLL key
is
not
pushed
in, the Terminal
goes
into the hold
screen
mode. The
cursor
returns to the start of
page
location
and blinks. All external
inputs are
disabled when this
occurs. Data can only be
transmitted
out of
the Termi-
nal by the keyboard. The Terminal stays
in
the hold
screen mode until the SCROLL
key is
pushed
in
or
until the ERASE
PAGE key is
pressed.
You
can use this feature
in
conjunction
with the
paper
tape reader/punch
for reviewing program
tapes.
The
reader/punch
can read
the tape
at its maximum
speed
to fill
up the
screen
quickly,
then
after the last line
has
been written,
the
hold
screen mode
disables
the
handshake
signal
coming
from
the Terminal.
This
stops
the tape
from running.
You
can
then
review
the
contents
of the
screen.
When
you
are finished,
just
press
the
ERASE
PAGE
key
and receive
another
screen full
of
program
information
automatically.