IBM 5155 - The Typewriter Area

The Typewriter Area
Key positions in the typewriter area are much like those
of a standard typewriter. There are, however, some
additional keys that perform control functions for the
IBM Portable Personal Computer.
([§J)
The Caps Lock key when pressed once, locks the
characters A through Z in the uppercase position. You
can get lowercase characters while Caps Lock is on by
pressing the Shift key. Pressing the Caps Lock key
again releases the uppercase mode for characters A
through
Z.
3-8 Keyboard