The diagnostics test mode allows the user to select a basic(1),
advanced(2) or stress(3) series of powerup self tests to be run
when the acModuleOpStatus field is changed to selfTesting(4). A
basic(1) test performs a quick self test and is the mode which is
by default selected at powerup. Advanced(2) mode is used to run
a more thorough series of tests and stress(3) mode is used to
execute a system test packet loopback type of powerup test. In
all test modes, the acModuleDiagStatus field contains a unique
results code (Refer to diagnostics utility guide). The results
of a test request is also written as a string to the
acModuleDiagResultString field.