Designator Characters Tell You About The Data On Your Screen - IBM 3270 Operator's Manual

How It Is Used
In most applications for the selector light pen, a list or a table is displayed, and
the operator selects items from it with the selector light pen. Although all
applications are basically similar, a user's specific application could be unique.
Ask the appropriate person in your organization to explain your organization's
applications and the way you are to use your selector light pen.
There are two types of selectable fields that can be displayed on your screen:
(1) selection fields and (2) attention fields. You will use the selector light pen
to (1) select items in selection fields, and (2) notify the program of your selec-
tions by selecting an attention field.
The first character of each selectable field on your screen is called a designator
character. The designator character for a selection field is either a question
.mark (? ) or a greater-than sign (
> );
the designator character for an attention
field is an
~mpersand t
&) or a blank position. See Figure 4-3.
Figure 4-3. Designator characters tell you about the data on your screen.
Making Selections
To see more clearly which fields on your screen are light-pen-detectable, press
the end of the selector light pen against the palm of your hand. This will cause
lines to appear through alilight-pen-detectable fields.
Initially, the designator characters (the first characters) of most detectable items
on your screen will be question marks. To select an item, place the point of the
pen directly over any character in that item and push the pen tip against the
screen to detect it. The question mark at the beginning of that item changes to a
greater-than sign to indicate that the item has been selected. Positioning the pen
incorrectly (not directly over the intended character or over a character in another
item) can cause the wrong item, or no item, to be selected. Therefore, you should
always verify that the designator character has been changed after you have selected
an item from your screen.
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