National Instruments PCI-1411 - Manual (Page 6)

Conventions
The following conventions are used in this manual:
♦
The
♦
symbol indicates that the following text applies only to a specific
product, a specific operating system, or a specific software version.
This icon denotes a note, which alerts you to important information.
This icon denotes a warning, which advises you of precautions to take to
avoid being electrically shocked.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.