Lexmark 4I3 - Manual (Page 224)

Introduction
All operators should know the following:
Locations of printer parts
The use and functions of the operator panel keys
Forms loading and unloading
Ribbon changing
Problem solving
Model number and attachment type identification.
In addition, some operators might be responsible for the following
tasks:
Forms device installation and checkout
All operator panel functions and operation (including checking
and changing parameter values)
Print tests.
A-2 User’s Guide