Difference between Informatica Connected Lookup & Unconnected Lookup

Connected Lookup	Unconnected Lookup
Receives input values directly from the pipeline.	Receives input values from the result of a :LKP expression in another transformation
You can use a dynamic or static cache.	You can use a static cache.
Cache includes all lookup columns used in the mapping (that is, lookup table columns included in the lookup condition and lookup table columns linked as output ports to other transformations).	Cache includes all lookup/output ports in the lookup condition and the lookup/return port.
Can return multiple columns from the same row or insert into the dynamic lookup cache.	Uses one return port (R). Returns one column from each row
If there is no match for the lookup condition, the Informatica Server returns the default value for all output ports. If you configure dynamic caching, the Informatica Server inserts rows into the cache.	If there is no match for the lookup condition, the Informatica Server returns NULL.
Pass multiple output values to another transformation. Link lookup/output ports to another transformation.	Pass one output value to another transformation. The lookup/output/return port passes the value to the transformation calling: LKP expression.
Supports user-defined default values.	Does not support user-defined default values