IBM 3270 Operator's Manual page 25

Normal/Test Switch
When you are operating the display station, this switch will be in the Normal
position.
You will use the Test position of this switch when you have a problem with the
machine and you perform the problem determination procedures. When you
place the switch in the Test position, you can perform the tests that are described
in Section 3 of the 3278 Problem Determination Guide.
Dual Case/Mono Case (A,a/A) Switch
You can use this switch to cause your display station to display
(l)
only upper-
case alphabetic characters or
(2)
both uppercase and lowercase characters. To
select only uppercase characters, set the switch to A; to select uppercase and
lowercase characters, set the switch to A,a.
However, the position of this switch does not determine whether uppercase or
lowercase alphabetic characters are sent to the host system. For example, if the
switch is set to A and you enter a lowercase e character, an uppercase E
char-
acter is displayed on the screen; however, when the character is sent to the host
system, the code for a lowercase e character is sent.
Video Test Switch
If your display station has the IBM 3270 Personal Computer Attachment
installed, the Video Test switch is located in a panel on the back of the display.
This switch does not affect the display and can be in any position during display
operation.
You will use the Test Mono and Test Color positions of the switch when you
have a display station problem and are performing problem determination.
2-10
Normal
8
Test
A,a
[3
A
Test Mono
8
Normal
Test Color