Try using the database feature and see if that department has something posted about their 10 codes. Many departments have switched to plain speak to eliminate errors in communication.
its up to the local agency - most 10- codes are easly figured out like for fire calls, motor vehicle crashs, medical calls just takes careful listening...
Like everyone said, it varies from county to county. In Ocean Co. 10-9 is arriving on scene, but in a few Atlantic Co. towns it means phone call. There are some standard ones across the board like 10-4, or 10-7 (out of service/off radio)
As others have stated, it would help to know what department your talking about. For example, in New Brunswick a "Signal 11" is a Hit & Run MVA, while a "39" is an MV stop.
Click on this link for the Woodbridge Twp. Database. Middlesex County, New Jersey (NJ) Scanner Frequencies and Radio Frequency Reference
On the left side, near the top, click on Wiki.
When the page comes up you'll see a list of Woodbridge Township Police Codes and Fire Pager Tones.
At the bottom of that page click on "Edison Township. Includes Fire and Police Signal Codes"
Those are the only code/signal lists available for Middlesex County.