Type of trunks?
I suspect Analog loop start. If I am guessing correctly, then the system is probably programmed to expect Calling Line ID (CLASS), but the CO trunks are not delivering. The 3300 is waiting for the CLID before sending the call to your phone, that is the delay you experience. Program the CO trunks to not expect CLID and you should be good. That is of course if I guessed correctly!
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If you are not part of the solution...
Then there's good money to be made in prolonging the problem.