look at
http://www.asustor.com/product/comparisionCompare the AS-202TE with another (e.g AS-5102T)...
AS-202TE = Memory 1GB Memory DDR3
AS-5102T = Memory 2GB SO-DIMM DDR3L (Expandable. Max 8GB)
If a product allows expansion of Memory, it is stated along with the max.
The AS-202TE has the RAM chip built in to the motherboard, so it cannot be removed and replaced (short of un-soldering and then soldering on a new chip).