Each town in BurlCo is assigned a district number.
For instance Westampton is District 27. Police, Fire and EMS all use 27 as their district "identifier" so to speak.
For the Fire Departments, the fire houses are numbered after the District number. I'll keep with the Westampton example:
The Fire Department in Westampton is Station 272......27 for the district and number 2 for that specific station. The station numbers usually arent reassigned, there used to be a 271 and 273 (they were both in Rancocas and are now disbanded).
The EMS stations in the same town still use the District number, but their stations are 7, 8 or 9. Again, in Westampton the EMS side of the firehouse is 278.
Engines, Ladders, Rescues and Ambulances are also numbered - after the district number and station number.
Engine 2721 (District 27) (Station 2) Apparatus 1 - 27-2-1.......There is a theory behind the numbering the individual apparatuses, but I dont want to confuse you so we'll stop it here.
Ambulances follow suit 2781 ----- District 27, Station 8, Ambulance 1.......Theres a 2781, 2782 and 2783 presently.
The Chiefs and line officer's numbers vary from Dept to Dept, but they all follow the District number first.
Let me know if you want the Police radio explanation.
Hope this helps.