If I'm not mistaken, they use a select few APCO ten codes that are shared with Monroe County (at least for the most part). These are from my Monroe County notes, but they should be valid for Livingston County:
10-4: Affirmative or acknowledgement
10-7: Out of service
10-8: in Service
10-9: Repeat
10-27: ID check
10-28: Vehicle check
10-29: Warrant check
10-78: Emotionally disturbed person
10-97: On scene
You might also hear "Code 500," meaning cardiac arrest, and "Code 9-8-0," meaning deceased.
And I would imagine you're already aware, but you also have the priority codes system in use, with "Priority 1" being the highest, and "Priority 4" being the lowest.