Basic Features
Key Presses and the Secondary Function : Key
To execute the function associated with a key, press and release the desired key. Most of the 20b's keys have two functions: the primary function and the secondary function. The primary function is printed on the top of the key. The secondary function is printed on the bevel of the key. See Figure 2.
Primary
Function
R
Secondary
(shifted) Function
Figure 2 Primary and Secondary Key Functions
To activate the secondary function of a key, press and release :followed by the key with the desired secondary function printed on the bevel. Unlike the shift key on a typewriter or computer keyboard, it is not necessary to press and hold : while pressing another key.
When :is active, the down arrow annunciator appears on screen, indicating that the next key pressed will execute the
secondary function of the key. To cancel an accidental press of :, simply press :a second time.
In this manual, commands using the secondary key functions are represented by the secondary function key symbol, :, followed by the key with the secondary function. For example, to execute sine, press :p. Note how the SIN portion of the key is highlighted, while the 7 is grayed out. This highlighting focuses on the function of the key that will be activated in a given command, and it is used throughout the manual to make the examples easier to follow. Key commands for example problems are provided throughout the text and in tables. Key symbols are placed in the order they are to be pressed, from left to right.
Annunciators
Annunciators are symbols that appear in the display as messages, or after certain keys or key combinations have been pressed. Annunciators are special symbols indicating a specific status in the calculator. Figure 3 illustrates the annunciator symbols in the display.
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