This feature can help diagnose communication problems between a PC and an analyzer system and switching problems on an analyzer. The two (2) types of tests that can be run are the Loop Back Test and the Switch Test. The Loop Back Test diagnoses communication problems between a switching system and its connected Host PC. The Switch Test is used to check switching operations in the system.
Source: NETS User Manual, Revision D, document 132-06035-0006, section 8.2.3.3.