FDNY Radio Terminology

Listening to the FDNY can be confusing. Until you develop an ear for the format of the announcements, and understand what all of the numbers mean, it could be like listening to gibberish. In this writing I will explain some typical radio terminology. The 10 codes are defined on a separate page.


Approximately 60 seconds after a box is transmitted the radio dispatcher announces the box. A typical transmission is formatted thus: borough, source of the alarm, box number, address, what the caller is reporting. The different types of sources are: telephone (Via 911, direct dial, operator assist, TDD, etc.), ERS (street box that allows voice contact), pullbox (mechanical street box sometimes simply called "box"), DR (discretionary response) box (Mechanical street box with a high false alarm rate. The battalion chief may respond at his discretion.), verbal (reported to us by a member of the department), class-3 (alarms from central station monitoring companies), and EMS or EMS-PD (CFR runs that are received by direct computer link).

Addresses in the borough of Queens are mostly numeric and the untrained ear may not be able to decipher the announcement. For example, the address 158-24 81 Street between 158 & 159 Avenues when spoken quickly may sound like just a string of numbers.


Since the inception of E911 some years ago this phrase has been sneaking into our lexicon. At first we were saying, "As per the E911 Computer the caller is at..." But that phrase has been shortened to, "The Annie Alley location is..." Annie Alley of course being the phonetic pronunciation of ANI-ALI.


Some of the old telegraph bell signals are still used on the radio. The most common are, 5-7 (1 engine, 1 ladder response), 65-2 (department message), and 5-5-5-5 (line of duty death).


The use of the letter K is a holdover from the days of telegraph. It was sent at the end of a transmission to indicate that I am finished sending and I await your reply. It is similar to the military use of the word over.


BISP stands for Building Inspection Safety Program and is also called simply Building Inspection (B.I.)


There is no legal description of the term taxpayer as used in this department. It's meaning is derived from the practice of real estate investors who, while holding parcels of land for speculation, constructed cheap buildings that could house multiple tenants. The rent collected would be used to pay the taxes on the land. This type of building commonly houses multiple commercial tenants. Outside of New York City the closest comparison I've seen are buildings called strip malls.

Modern taxpayers are not constructed so cheaply but they do contain some of the inherent dangers of their older counterparts. For example: little or no fire stopping between subdivisions over the ceiling, common cellars or cocklofts that run the length of the building, etc.


Some building types you may hear are class 1 or class A meaning fireproof, class 3 meaning non-fireproof (NFP), OLT meaning Old Law Tenement (apartment houses built prior to April 1, 1901), and NLT meaning New Law Tenement (apartment houses built between 1901 and 1929). The term tenement is not used to describe buildings built after 1929.


In early April, 1999, the department began a campaign designed to educate the general public in fire safety. All units are handing out flyers with information on how to avoid being a fire casualty. They go door-to-door, hand out these flyers, and talk to the citizens in their response area. This campaign is called "Operation Firestop".


"Attention units responding to box 1234, Sids information available upon request." We're not talking about a person called Sid. The Critical Information Dispatch System (CIDS) was invented to provide fire fighters with information that might be helpful while operating at a fire scene. While companies are out on building inspection they make note of special conditions that can affect their operation. Typical entries contain the height, dimensions, occupancy, and construction of the building; the location of standpipes; the location of hazardous materials stored within; or any other critical information.


Our radio system (for now) is a 2 channel simplex voting receiver type. We transmit on one frequency and receive on another. This gives us in the Central Office the ability to transmit and receive at the same time. The frequency you listen to is the output of the Central Office. In order for you to hear what we hear, we have to turn on the "mixer".This device injects our receive audio into the transmitter. When a unit wants to give us sensitive information they ask us to turn it off, thus preventing anyone listening from hearing the transmission. It's not fool-proof though. Anyone within range of the low power transceiver of the unit can monitor the output frequency of the mobile and hear the message.


MUD - Multi-unit drill.
ADV - abandoned derelict vehicle fire (10-23)
MUNGO - a fire in a 55-gallon drum used by vagrants to melt insulation from copper wire.
REAR TENEMENT - a building situated behind another that doesn't front on a street. The only means of egress is through the building in front.
FAST UNIT - a company assigned to an incident that stands by in case a Mayday is transmitted. This policy is the city's equivalent of the OSHA 2in-2out rule. Usually it is a ladder company, but it can be an engine company if the Supervising Dispatcher feels truck availability will suffer.
FALLBACK - During times of heavy activity we implement Fallback to reduce the amount of apparatus assigned to an incident. This preserves unit availability. There are 3 steps:

  • Step 1
    • Nearest available unit (Engine or Ladder) on electromechanical boxes.
    • Class-3 maximum response: 1 Engine, 1 Ladder and 1 BC.
  • Step 2 = Step 1 AND
    • Class-3 response: Nearest available Engine or Ladder.
    • CO Detector: 1 Ladder or nearest available CO meter equipped unit.
    • Water leak: Nearest available Engine or Ladder.
    • SOC matrix response that requires a Structural Response: 2 Engines, 1 Ladder, 1 BC and SOC units.
  • Step 3 = Step 2 AND
    • Structural Responses: 3 Engines, 1 Ladder and 1 BC (Note: On a verified second source: 3 Engines, 2 Ladders and 1 BC)
    • SOC matrix response that requires a Structural Response: 1 Engine, 1 Ladder, 1 BC, nearest available Rescue and Squad and nearest available SOC Support Ladder. (Note: On a verified second source: fill out to normal SOC matrix response)
    • Gas Leaks, odors of gas or similar odors: 1 Engine and 1 Ladder.
    • Manhole Fires: 2 Engines, 1 Ladder and 1 BC.
    • Minimum responses, based on CIDS or Box numbers, are suspended. Responses will be based on information received.

DOUBTFUL? There are 4 terms we use to indicate the control of a fire:
  • Doubtful will hold - The chief is doubtful the fire can be controlled with units already assigned -- more may be needed.
  • Probably will hold - The chief probably can control the fire with units assigned.
  • Will hold - Self explanatory but rarely used.
  • Under control - Self explanatory.

If you need clarifications of other terms and phrases let me know.