Most responders learn early that ICS calls for common terminology and plain language on the radio, and many assume the rule arrived in one piece after one disaster. The record is less tidy. The clear text convention came out of the FIRESCOPE work in 1970s California and spread through wildland agencies for decades. Federal adoption through HSPD-5 in 2003 and the NIMS documents that followed then made it a national expectation. This piece separates what NIMS actually requires from what local agencies chose on their own, because confusing the two causes real trouble when units from different places share a channel.

Clear text in the ICS design: what the term meant then and means now

When the FIRESCOPE agencies built the Incident Command System in the 1970s, they treated radio language as part of the terminology problem rather than as a separate subject. The California ICS documents that grew out of that work, including the field operations guide FIRESCOPE still maintains, have long told users to transmit in clear text. In ICS usage that means ordinary words in place of numeric codes or agency-specific shorthand. The reasoning followed from the rest of the system. A standard position title or resource type only helps if the listener hears it in a form they understand. A ten-code that means one thing to a city engine company, and something else or nothing to a federal hand crew, undoes the work the standard titles were meant to do.

The term causes a predictable confusion in radio shops today. In ICS, clear text describes the language of a message. Radio technicians say a transmission is “in the clear” when it is not encrypted, so a talkgroup running clear can be heard by anyone with a compatible receiver. The two meanings have nothing to do with each other. A transmission can be clear text and encrypted, or full of codes and unencrypted. I have sat in meetings where both senses came up within a few minutes, from people who assumed everyone knew which one they meant. When it matters, I say “plain language” for the first sense and “unencrypted” for the second. FEMA’s NIMS material generally uses plain language and often treats the two ICS terms as equivalent, which is the usage I follow here.

Clear text in the ICS sense was written for incident communications. Nothing I have read in FIRESCOPE’s published history suggests the program tried to tell its member agencies how to run daily dispatch traffic. Agencies in California and elsewhere kept their own internal codes for decades after ICS was in use. That split between incident doctrine and daily habit runs through the rest of this story. It explains most of the arguments that came later, when a federal document appeared to reach into the daily traffic of every agency that took preparedness money.

A pattern of findings rather than one fire

The version of this history that circulates in classrooms usually has a single cause. Sometimes it is the 1970 California fires, sometimes September 11, and occasionally Hurricane Katrina, depending on who is teaching. The written record supports a pattern instead. FEMA’s introductory ICS course lists conflicting codes and terminology among the general weaknesses of responses that lacked a common system, alongside poor accountability and overloaded commanders. It presents these as recurring problems and does not tie them to one event. The 1970 fires are where FIRESCOPE wrote the problem down and designed against it, and the companion article on this site covers that period. They are the start of the documented pattern, not the whole of it.

The convention spread with ICS itself. The National Wildfire Coordinating Group adapted the FIRESCOPE system for national interagency wildland use in the 1980s, which carried clear text radio practice into federal and state wildland agencies across the country. Structural fire departments, law enforcement and EMS adopted ICS unevenly through the 1980s and 1990s. Codes stayed in daily use in many of those disciplines even after the agencies said they ran ICS. Each time one of those agencies worked a large incident beside agencies with different codes, the same friction appeared. Over those years, after-action reports from many large multi-agency responses listed communications and terminology among their problems. Those reports are spread across many agencies and are not collected in one place. Anyone making a specific claim should cite the specific report rather than a summary of the trend.

The September 11 investigations documented serious communications failures at the World Trade Center, and two other articles on this site deal with them directly. As I read those findings, they centered on coordination between agencies, command relationships and radio performance in the buildings, not on ten-codes. Presenting them as the origin of the plain language rule overstates what they say. What September 11 did produce was the political push for a national incident management system. That push gave an existing wildland convention a federal home, which is a different thing from the attacks causing the convention to exist.

HSPD-5 and the first NIMS: a California convention becomes a federal condition

Homeland Security Presidential Directive 5, titled Management of Domestic Incidents, was issued on February 28, 2003. It directed the Secretary of Homeland Security to develop and administer a National Incident Management System. The directive describes NIMS as including a core set of concepts, principles, terminology and technologies, covering the incident command system, multiagency coordination, unified command, training, and the identification and management of resources, among other elements. That is a paraphrase, and the full text is available through the Department of Homeland Security and the federal government’s archives of presidential directives. The word terminology appears in the directive itself. That is worth knowing, because it shows common terminology was part of the federal requirement from the first document and not a later addition.

The directive also said that beginning in fiscal year 2005, federal departments and agencies would make adoption of NIMS a requirement for providing federal preparedness assistance to states and localities. That provision is why most responders met ICS as a training requirement attached to a grant. It is also why radio language that had been a wildland convention became something a county administrator could be asked about during a compliance review. I find no reference to ten-codes or radio procedure in the directive. The plain language specifics came in the documents and guidance written to implement it.

The first NIMS document was published on March 1, 2004. Its communications guidance called for plain English, rather than codes, in incidents involving multiple agencies, jurisdictions or disciplines. In the years after 2004, plain language appeared among the NIMS implementation objectives that states and localities were asked to meet. The specific metrics changed from one fiscal year to the next. FEMA’s archived NIMS compliance documents are where to confirm what applied in a given year, and I would not rely on anyone’s memory of those metrics, including my own. Revised NIMS editions followed in December 2008 and October 2017. The 2017 edition is the current national document as I write this, though FEMA can revise or supplement it, so check the current version before you cite it.

The ten-code clarification and the myth of a federal ban

As agencies worked through NIMS implementation, the plain language expectation ran into one of the most entrenched habits in public safety radio. Ten-codes had been in American police radio since the late 1930s and early 1940s, promoted through APCO and revised over the years, and many agencies had added local variations. A separate article on this site covers where that debate stands now. For this piece, what matters is how the federal guidance drew the line. The NIMS Integration Center, the FEMA office then responsible for NIMS, issued plain language guidance in the 2005 to 2006 period. It said plain language was required for multi-agency, multi-jurisdiction and multi-discipline incidents. For internal agency operations, the guidance said plain language was not required but was strongly encouraged. The stated reason was that responders perform better in an emergency when they use the same language every day.

News coverage at the time produced headlines saying the federal government had banned ten-codes. That claim is a myth, and it still circulates in departments. The guidance did not prohibit codes in an agency’s own daily traffic. It required plain language when agencies came together on an incident, and it urged agencies to adopt plain language internally so their people would not have to switch habits under stress. The urging carried real persuasive weight, and some agencies and states moved to plain language for all traffic partly in response. When they did, that was their own decision, made through their own policies.

The practical consequence is that an agency still using ten-codes for routine traffic is not, for that reason alone, out of line with NIMS. What NIMS expects is that the same agency’s people switch to plain language on a multi-agency incident and can do it reliably. The weak point is that most people cannot switch reliably on a bad day, which was the federal guidance’s own argument for going further. An agency keeping codes internally should know it is relying on its members to change languages at the worst possible moment, and should test whether they can. Your state emergency management agency can tell you whether your state attached any additional requirement to grant funding.

What current NIMS doctrine requires, as far as the documents go

The 2017 NIMS document lists common terminology among the NIMS management characteristics. It describes common terminology as what lets different organizations work together across functions and hazards. It applies the idea to organizational functions, position titles, resource descriptions and incident facilities. In practice that means an incident commander, a staging area, an operations section chief and a Type 1 engine should mean the same thing regardless of which agency’s member says them. The resource descriptions connect to the national resource typing definitions FEMA maintains. The position titles connect to the qualification framework FEMA publishes for incident personnel. For exact current wording, go to the NIMS document itself and to FEMA’s NIMS resources pages rather than to a training slide.

On radio language, the national doctrine keeps the plain language expectation for incidents that involve more than one agency, jurisdiction or discipline. The ICS training courses continue to teach plain language and common terminology as basic requirements. The doctrine does not script radio phrasing. It does not provide a list of approved words, a format for unit identifiers, or a procedure for priority traffic. Those gaps are intentional, as far as I can tell, because the national document sets principles that agencies of very different sizes and disciplines can apply. Detailed procedure is left to the agencies, the states and the regional plans.

The requirement also has a different character than a regulation. NIMS adoption is tied to federal preparedness assistance, and states have handled implementation reporting in their own ways over the years. Some have folded NIMS expectations into state law or executive orders, so an agency’s obligation can come from several layers at once. When a chief asks me what the agency must do, the honest answer is that the national baseline is plain language and common terminology on multi-agency incidents. Beyond that baseline, the obligations depend on the state, the grant and any regional agreements the agency has signed. The state emergency management agency is the right office to confirm which layers apply.

What local agencies chose on their own

Much of what responders think of as ICS radio language is local choice that fits within ICS. Unit identifiers are the clearest example. A unit called Rescue 1 is an ALS transport ambulance in many Florida departments and a heavy rescue company in many Northeastern ones. Squad means a small attack unit in one place and a technical rescue company in another. Medic, Ambulance and EMS each name transport units somewhere. NIMS defines resource kinds and types for ordering and tracking. It does not dictate what an agency paints on the side of a truck or says when keying up. That is why a unit’s radio name can tell a dispatcher from another county almost nothing about what the unit carries.

Priority traffic is another area where the vocabulary is local. Mayday is the internationally recognized voice distress word. The fireground procedure around it is not set by NIMS: who acknowledges, what the member reports, and how the channel is cleared. Those details come from NFPA standards, state training and local SOPs, which other articles on this site cover. Terms like “emergency traffic,” “priority traffic” and “urgent” mean different things in different departments, and in some places they mean nothing at all. Status words vary too, including “on scene,” “on location,” “in service” and “available,” and so do conventions such as twelve-hour or twenty-four-hour time on the air.

Naming conventions for command also tend to be local practice that fits ICS. Many fire departments name command after the street or the incident, a habit that spread through the structural fire service with the Phoenix fireground command model and similar local systems. NIMS asks that incidents be identified and that the incident commander be clearly established. It does not prescribe the exact phrase, so two departments that both run ICS correctly can still announce command in different words. None of these local choices conflicts with NIMS on its own. The conflict appears when an agency’s members believe their local terms are the national terms and use them with a partner who has never heard them.

Plain language still needs standard phrases

A common misreading of the plain language requirement is that any ordinary English will do. Agencies that dropped codes without replacing them sometimes found their channels filling with longer, looser transmissions. Members were describing in full sentences what a code had once said in two syllables. Plain language works on a busy channel only when the agency also settles on standard phrases, so the words are ordinary but the structure is predictable. “Affirmative” and “negative” persist in many plain language agencies because a clipped “yes” or “no” is easy to lose in a weak signal. A fixed order for a size-up or a progress report lets the listener know what is coming before the speaker finishes.

Structured report formats used on many firegrounds, such as conditions, actions and needs, are local or regional conventions rather than NIMS requirements. They show what a plain language agency needs alongside the policy. The format carries the order and the words stay plain, so a mutual aid officer who has never used the format can still understand every word of the report. That is the property that makes plain language useful across agencies, and it is lost when an agency’s standard phrases drift into private shorthand that works like a code.

Ambiguous ordinary words need attention as well. Depending on who says it, “clear” can report a completed search of an area or a unit’s finished assignment, radio technicians use the same word for an unencrypted transmission, and some command officers use it to announce that the whole incident is over. “Copy” splits more narrowly, since some agencies treat it as confirmation that a message was received while others take it to mean the message was understood, and “hold” can be heard as stop, wait or maintain position. Agencies that write a short list of defined words for their SOP, and teach it in recruit training, get most of the benefit of codes without the interoperability cost. The NIMS documents leave that list to the agency, so if your agency has not written one, nobody else will have written it for you.

Where the two meet: mutual aid, dispatch and the CAD

The difference between national requirement and local choice mostly stays invisible until units cross a boundary. On automatic aid and mutual aid, the receiving agency’s dispatcher hears another agency’s unit identifiers and status words. The incident commander hears another agency’s habits, and members from both sides hear each other’s shorthand. The dispatcher often ends up as an informal translator, converting a neighboring department’s unit name into the resource type the incident needs. That work goes unnoticed when it goes well. When it goes badly, the incident commander gets the wrong apparatus or waits while someone sorts out what was actually sent.

The computer-aided dispatch system holds a version of the same problem in its unit type codes and status codes. Two neighboring CAD systems can use the same abbreviation for different equipment, or different abbreviations for the same equipment. Agencies that have connected their CAD systems usually discover these mismatches during integration, if not sooner. Reconciling a mutual aid partner’s unit types against the national kind and type definitions is tedious work. It is also the same work FIRESCOPE did in the 1970s, done again at the level of a database.

Interoperability channels have their own naming layer. The national interoperability channels carry standardized names developed through the National Public Safety Telecommunications Council. These are the call and tactical channel designators listed in the National Interoperability Field Operations Guide that DHS publishes. Many agencies have programmed those channels under the standard names, though some still use older local labels. A mutual aid radio plan that names a channel one way when half the incoming radios display it another way recreates the terminology problem at the channel selector. The current NIFOG and your statewide interoperability coordinator are the references for the standard names. The ICS-205 for any multi-agency incident should use them as written.

What to do at your agency

• The operations chief reads the agency’s current radio SOP and writes one paragraph stating whether internal traffic uses plain language or codes, and that plain language is mandatory on any incident involving another agency, then submits it through the agency’s normal policy revision process.
• The communications center supervisor pulls the unit type and status code tables from the CAD system, compares them with those of each automatic aid partner, and sends the chiefs a written list of every code or unit name that means different things in different agencies.
• The training officer adds a fifteen-minute block to the next scheduled company drill in which crews run a mock multi-agency incident on a practice talkgroup with codes prohibited, and records each transmission where a code or private shorthand slipped through.
• The radio system administrator checks the current codeplug for every national interoperability channel and confirms the channel names match the standard designators in the current NIFOG, then logs any mismatches for correction at the next programming cycle.
• The emergency management coordinator asks the state emergency management agency’s NIMS point of contact for the current state document describing NIMS and plain language expectations tied to preparedness funding, and files it with the agency’s grant records.
• The fire or EMS chief adds one item to the agenda of the next existing regional chiefs’ or mutual aid meeting: agreeing on a short shared list of defined radio words, starting with clear, copy and emergency traffic.

Takeaways

• Clear text radio traffic began as part of the FIRESCOPE ICS design in 1970s California, where it extended common terminology from titles and resource names to the language spoken on the air.
• In ICS usage clear text means plain language without codes, which is unrelated to the radio shop’s use of “in the clear” to mean unencrypted.
• The record shows a pattern of terminology and communications findings across decades of multi-agency incidents, so no single fire, attack or hurricane should be taught as the sole cause of the plain language rule.
• HSPD-5, issued February 28, 2003, named terminology among the core elements of NIMS and tied NIMS adoption to federal preparedness assistance beginning in fiscal year 2005.
• The idea that the federal government banned ten-codes is a myth, because the NIMS guidance required plain language on multi-agency incidents and only encouraged it for internal traffic.
• Current NIMS doctrine requires common terminology for functions, position titles, resources and facilities, along with plain language on multi-agency incidents, but it does not script phrases, unit names or priority traffic procedures.
• Unit identifiers, status words, priority traffic terms and command naming are mostly local choices, and they cause errors when members assume local terms are national ones.
• Plain language works on a busy channel only when the agency also defines its standard phrases and settles the meanings of ambiguous words such as clear and copy.