Figure 3-19.—A PPI equipped with a 6 x 7
panel and a keyboard.
label for each switch position on an individual basis.
The category selection switches provide for
When depressed, each switch position generates a
specific function code for computer input. A single
LED indicator at the top of the panel is lighted to cue
operator responses or to indicate reception of switch
function codes.
A 6 by 7 Panel.— A 6 by 7 panel consists of 7 rows
of 6 switches as shown in figure 3-21. When
depressed, each of the 42 switches generates a specific
function code for computer input. The 6 by 7 panel is
used for category selection and as a data entry unit for
numeric data. The top two rows of switches and the
first three switches on the left in the remaining rows
are used for category selection.
The remaining
switches are used as a number entry unit.
independent console control of the symbology
displayed at that console. The console operator can
select the category of the symbols to be displayed on
the console.
The number entry unit consists of a 10-digit
keypad, a clear button, and four special-purpose
buttons.
Numerical entries from the keypad are
displayed on the console CRT until one of the special-
purpose buttons is depressed and the number entered
is accepted by the computer program.
Alphanumeric Keyboards.— The alphanumeric
keyboard installed in some consoles is a series of
switches that inputs a code to the computer when a
switch is depressed
3-15
