Rung any old number that’s announced (6)
I believe the answer is:
spoken
'announced' is the definition.
'rung any old number' is the wordplay.
'rung' becomes 'spoke' ('spoke' can be a synonym of 'rung').
'any old number' becomes 'n' (used to represent any number in maths).
'spoke'+'n'='SPOKEN'
'that's' is the link.
(Other definitions for spoken that I've seen before include "Uttered through the medium of speech" , "released from trap" , "Voiced" , "Verbalised" , "Said" .)