Friendly communication accompanying a note (8)
I believe the answer is:
amicable
'friendly' is the definition.
(associated in meaning)
'communication accompanying a note' is the wordplay.
'communication' becomes 'cable' (cable is a kind of communication).
'accompanying' is a charade indicator (letters next to each other).
'note' becomes 'mi' (as in 'do re mi').
'a'+'mi'='ami'
'cable' after 'ami' is 'AMICABLE'.
(Other definitions for amicable that I've seen before include "Friendly, peaceable" , "Friendly, good-humoured" , "Friendly, nonthreatening" , "Friendly, peaceful" , "warm" .)