Telephone call permits curls (8)
I believe the answer is:
ringlets
'curls' is the definition.
(I know this)
'telephone call permits' is the wordplay.
'telephone call' becomes 'ring' (I've seen this in another clue).
'permits' becomes 'lets' ('let' can be a synonym of 'permit').
'ring'+'lets'='RINGLETS'
(Other definitions for ringlets that I've seen before include "Spiral curls" , "Sterling sort of curls" , "Curls, of Irish dancers say" , "Curls or tendrils" , "Locks" .)