My EX-21 came with a dust collection port. It is a 2.5" female vacuum connection. I have a small 1.25" Stanley vacuum that I used with my P-C saw (P-C has a 1.25" female vacuum fitting).
I found vacuum adapters from a 2.5" male hose to a 1.25" female fitting but none from 1.25" male hose to 2.5" female fitting.
The pics below show a plug cut from 3/4" pine board. The outer circle was traced from the 2.5" female and then cut with a 10 degree angle, tapered smaller toward the saw. The inner hole was traced from the 1.25" male and cut with a 2 degree angle also tapered smaller toward the saw. The inner hole is cut off center to help pick up dust that gravity has pulled down inside the bigger female fitting.
The 10 degree plug fits nice inside the 2.5" female, and the 1.25" male hose, which is already tapered to fit into a 1.25" female, is snug in the 2 degree inner hole.