Depends what County he was from. For example, HPVFD is Station 37 here in Middlesex county. Now, if you go to say Mercer, or Somerset, or Hunderton, 37, if used, is obviously a different town.
In Dover Twp. the Police Community Service EMT Unit is Squad 51. It was established to suppliment the volunteer squads because of lack of enough coverage during the day. The units are designated as Med 1, 2, 3, & 4.
typically, but not always, departments go by their municipal number (last two digits) within their county taxation code listed here: http://www.njdivisionoftaxation.com/pdf/lpt/cntycode.pdf#search='nj codes 1022 1024'
but sometimes have to use variations or made-up numbers if there is confusion from surrounding departments, but Morris doesn't have a 14(51) unless its Boonton which is 1401 and they used a 5 first, composing 51. That may sound silly but counties like Hunterdon did this because townships like Clinton are listed as 1005 in the taxation codes, and station 5 doesnt sound as distinct on a radio as station 45. Hope that makes sense!