Ring inventor (4)
I believe the answer is:
bell
I believe this is a double definition.
'ring' is the first definition.
(both can mean to call on the phone)
'inventor' is the second definition.
(Alexander Graham Bell)
(Other definitions for bell that I've seen before include "Scottish-born inventor of the telephone, d. 1922" , "''The ... Jar'' (Sylvia Plath)" , "See 8" , "It makes a ringing sound when hit with a clapper" , "Alexander ..., inventor of the telephone" .)