“Ducted inlet or ducted outlet dBA @xx Ft.” (Distance can be user adjusted under preferences) 
Sound Pressure at a Distance refers to an arrangement where the fan is assumed to sit in a free (infinite) field with a dBA meter positioned some distance from the fan, such as 15 feet. A duct runs from either the fan inlet or the outlet for a large distance, such that any sound from the end of the duct does not affect the dBA readings. Most of the measured sound will come from the non-ducted inlet or outlet.
(Note regarding “or”: While the sound power from a fan inlet and outlet are likely to be somewhat different, it is a popular and practical simplification in fan engineering to assume that they are the same.)
“Ducted inlet and ducted outlet dBA @xx Ft.” 
When both inlet and outlet are ducted far away the fan sound pressure measured near the fan is greatly reduced, as only the fan casing, (motors and drives in some cases), duct connection and the ductwork itself typically remain as sound sources. Commonly accepted reductions are 15 to 35 dBA, 20 dBA is used here.
(Note: “Ducted inlet” and “Ducted outlet” terms as used here should not be confused with the same terms used by AMCA to define sound test arrangements.)
It should not be assumed that sound pressure levels as shown here will be reproducible in actual applications because the assumption of a “free field” with no reflections or other sound sources is unrealistic. It is used because it has the advantage of being simple, clear, and easily defined. It provides an easy method for comparison of different fans.