Appendix A. Glossary - IBM 3278 Series Maintenance Information

Appendix A. Glossary
The terms defined in this glossary apply to the 3278
Display Station and its attachment to the 3274 and
3276 Control Units.
Analog card: A circuit card that converts digital
information into high·level signals for writing
characters on the display screen.
Attribute: A byte of <lata that specifies the kind of
display field. An attribute can specify the field as
protected or unprotected, for numeric, alphanumeric,
intensity, selector·pen detectability, and modification.
Bell: The sides of the cathode·ray tube (CRT)
between the display screen and the neck. (See
Figure 5·2.)
Blanking: The ability to prevent writing on the
screen.
Clicker: An assembly that, when enabled, generates
a small sound when a key on the
~eyboard
is pressed.
The sound indicates to the operator that the keyboard
has recognized the key pressed.
Coax: A shielded cable containing a single conductor.
Cone shield: A shield mounted on the neck of the
CRT. (See Figure 5·1.)
Contrast: The difference in light intensity between
displayed characters.
Cursor: An underscore symbol that identifies a
character position in a screen display, usually the
character position at which the next character to be
entered from the keyboard will be displayed.
(D):
The logic type using three base cards. (See
Figures 1·1,4·6, and 4·7.)
Divider scan: The straight line that is continuously
written on the display screen above the bottom line.
(See Figure 3·1.)
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