Call up for reserve - the big, thick, blocky type that some are buzzing over locally (9,4)
I believe the answer is:
telephone book
'call up for reserve the big thick blocky type that some are buzzing over locally' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'call up for reserve' is the wordplay.
'call up' becomes 'telephone' ('telephone' can be a synonym of 'call up').
'for reserve' becomes 'book' (I can't explain this - if you can you should give a lot more credence to this answer).
'telephone'+'book'='TELEPHONE BOOK'
Can you help me to learn more?
(Another definition for telephone book that I've seen is " Reference work with numbers".)