IBM 3164 ASCII Manual page 151

Chapter 5. Programming considerations
Using the Set Character Attribute command to set the character attributes
5-64
The Set Character Attribute command performs functions similar to the Set
Field Attribute command except that it works on single characters and not on
the whole field. In addition, the CA does not occupy a character position on
the screen. CA is effective in all modes; echo, character. and block modes.
Character attributes are not positional; the character position to which they
refer is not fixed in the page, as is the case with a field. They are tied to their
characters and are deleted and inserted with them.
FA Data Characters.
CA
=
Character Attribute
FA
=
Field Attribute
FA Data Characters.
You can control the following characteristics of a character using this
command.
A non-display character is a character entered from the keyboard or coming
from the host which is not displayed in a field.
A high intensity character is a character which appears in either red or white
on the screen in Default Color mode. This attribute is ignored in Program
Color mode.
A blink character is a character in which the background matches the
foreground color in intervals. It appears as though the characters in the field
are flashing on and off.
An underline character is a character which is individually underscored.
A reverse character is a character in which the foreground color and the
background color are inverted.
f
c