Heathkit H9 Manual page 8

PLOT
When this key is pushed in, the text is blanked except
for the first line of the page. This first line, however, is
displayed on each of the four bottom lines of the
screen. The screen area above the bottom four lines is
divided into 128 scan lines. See Pictorial r-2. A dash,
one character wide, will appear above each of the
characters displayed in the bottom four lines. The
position of the dash above the bottom line (line 0) is
proportional to the binary value of the z-bit ASCII
code for that character. For example, a CTRL/SHIFT
P, or ASCII null, is all zeros, so its binary value is zero,
and it appears at the bottom of the 128 line space
directly above the ASCII null. Pictorial r-g fllustra-
tion Booklet, Page 2) gives the line number and the
ASCII code for each key entry. A RUB OUT (delete) or
all ASCII L's has a binary value of 727, so the dash
appears at the top line (line 128) in the space above
the rub out character.
In the plot mode, all characters are written into RAM,
but their special cursor movements are not im-
plemented. That is, a RETURN (carriage return) is
written into RAM, but the cursor does not move. Any
control character that appears in the text will flash.
Even though the lower-case alphabetic characters
cannot be generated from the keyboard, they can be
L I NE
( B IN ARY
VALU E I27)
LIN
( B IN ARY
VALU E O)
entered into RAM from the digital computer, Like all
other characters, the binary value of the lower case
characters is stored in RAM and the dash is d.isplayed
on the appropriate line in the 128-line space. Lower
case characters stored in RAM are displayed as the
characters represented by the ASCII words 010 0000
through o17 71,'17.
BAUD RATE
When this key is released (out), the Terminal will
operate at 110 baud. When this key is pushed in, the
rate is set by the BAUD RATE switch on the rear
panel. The rear panel switch selects either 300 baud
or the preset baud. The preset baud is determined by a
jumper wire on the I/O circuit board.
OFF LINE
When this key is pushed in, the Terminal is inhibited
from transmitting or receiving data from the serial
I/O, but it does not interrupt transmission or recep-
tion through the parallel I/O port. This lets you punch
or read tape on the paper tape reader/punch while the
Terminal is off line from the digital computer.
N ON -
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PICTORIAL \-2