Equipment including new telephone (4)
I believe the answer is:
ring
'telephone' is the definition.
('ring' can be a synonym of 'telephone')
'equipment including new' is the wordplay.
'equipment' becomes 'rig' (rig is a kind of equipment**).
'including' means one lot of letters goes inside another.
'new' becomes 'n'.
'rig' placed around 'n' is 'RING'.
(Other definitions for ring that I've seen before include "Circus arena" , "Group of criminals maybe" , "sound as a bell" , "Marriage token" , "Buzz" .)