Communicate with power (5)
I believe the answer is:
reach
This clue is a double definition.
'communicate with' is the first definition.
(I've seen this in another clue)
'power' is the second definition.
(reach is a kind of power)
(Other definitions for reach that I've seen before include "Attain - continuous extent of water" , "Succeed in getting to" , "Arrive at - stretch of river" , "It's an advantage for a boxer" , "Arrive at, attain" .)