Series of street calls (7)
I believe the answer is:
strings
'series' is the definition.
(I know this)
'street calls' is the wordplay.
'street' becomes 'st' (abbreviation).
'calls' becomes 'rings' ('ring' can be a synonym of 'call').
'st'+'rings'='STRINGS'
'of' acts as a link.
(Other definitions for strings that I've seen before include "Bowed instruments in the orchestra" , "Lengths of wire etc on a musical instrument" , "Undesirable conditions" , "Cords" , "Just; trade exhibition" .)