Ten-codes, also known as ten signals, are code words used to represent common phrases in voice communication, particularly by law enforcement and in Citizens' Band (CB) radio transmissions.
The codes, developed in 1937 and expanded in 1974 by the Association of Public-Safety Communications Officials-International (APCO), allow for brevity and standardization of message traffic. They have historically been widely used by law enforcement officers in North America but due to the lack of standardization, in 2006 the U.S. federal government recommended they be discontinued in favor of everyday language.[1]
Contents |
The development of the 10-codes began in 1937, at a time when police radio channels were limited, to reduce use of speech on the radio. Credit for inventing the codes goes to Charles "Charlie" Hopper. He was the Communications Director at the Illinois State Police, District 10, located in Pesotum, Illinois. Hopper was involved in radio for many years and saw a need to abbreviate radio transmissions on State Police bands.[2] Experienced radio operators know that the first syllable of a transmission is frequently not going to be understood, but is a necessary part of "tuning in"; hence preceding every code with "ten" allows a better chance of understanding the critical portion. Also, the radios of the day were based on vacuum tubes, with a small motor-generator, called a dynamotor, used to generate the high voltage (300–600 volts, depending on the type of radio) needed to operate the transmitter, and the dynamotor took 1/10 to 1/4 of a second to "spin up". The officers were trained to push the microphone button, then wait a moment before talking, but sometimes they would forget; preceding every code with "ten-" gave the radio transmitter time to come up to full power.
Ten-codes, especially "ten-four", first reached public recognition in the mid- to late-1950s through the popularity of TV's Highway Patrol with Broderick Crawford as the patrolman reaching into his cruiser to grab the mike to answer a call, always preceding his response with "10-4!" Ten-codes were later adapted for use by CB radio enthusiasts before its pop culture explosion in the late 1970s. The tremendous popularity of the 1975 "Convoy" song by C. W. McCall depicting droll conversation among CB-communicating truckers put several phrases, such as 10-4 for "understood" and what's your twenty? (10-20) for "where are you?" into common and enduring use in American English. The song was followed by a 1978 movie Convoy, which further entrenched the use of ten-codes in casual conversation.
As of 2011, ten-codes remain in common use, but have been phased out in some areas in favor of plain language.[1] Nineteen states were planning to change to plain English as of the end of 2009.[3]
Codes are often used inefficiently. For instance, an exchange that could be "1 Mike 1, 10-20?" "First and Main" might be more like "1 Mike 1, what's your 10-20?" "My 20 is First and Main"—it would be more efficient to simply ask, "1 Mike 1, where are you?" "I'm at First and Main." On the other hand, there are times when the use of codes is appropriate, even if less efficient than speaking "in the clear." For instance, using discreet codes for sexual assault, homicide, suicide and other such situations can prevent the victim and family from having to hear the description being broadcast to all within earshot. Even when the meaning is known, it is less of an emotional jolt to hear a set of numbers being rattled off than to hear the word for the crime.
While ten-codes were intended to be a terse, concise, and standardized system, the proliferation of different meanings may render them useless in situations where people from different agencies and jurisdictions need to communicate. For that reason their use is expressly forbidden in the nationally-standardized Incident Command System as is the use of other codes.[4]
In the fall of 2005, responding to inter-organizational communication problems during the rescue operations after Hurricane Katrina, the United States Federal Emergency Management Agency (FEMA) discouraged the use of ten-codes and other codes due to their wide variation in meaning.[5][6] The Department of Homeland Security's SAFECOM program, established in response to communication problems experienced during the September 11 attacks also advises local agencies on how and why to transition to plain language.[7] The New Orleans Police Department continued using 10-codes as of 2010.[8] One solution to the inter-jurisdictional problem would be to establish a universal standard for the most common 10-codes and disallow any others.[9]
While APCO International's current position states that plain speech communications over public safety radio systems is preferred over the traditional 10-Codes and dispatch signals,[10] an APCO Bulletin of January, 1940 lists 17 codes assigned as part of APCO Project 4; in 1973, APCO Project 14 provided a core list of codes from 10-1 to 10-39,[11] with "optional" codes above 10-39.[12]
A basic list (10-1 through 10-39) remains available on APCO's site.[13] Many additional codes have been added by individual local or regional first-response agencies; these are not standard across jurisdictions and may be problematic if multiple organizations must respond to the same incident. Only a handful of codes are standardized.
California Penal Code sections were in use by the Los Angeles Police Department as early as the 1940s, and these code numbers are still used today instead of the corresponding ten-code. The best-known include:
Generally these are given as two sets of numbers—"One Eighty-Seven" or "Fifty-One Fifty"—with a few exceptions such as "459"—Burglary, which is given as "Four-Five-Nine".
The New York Fire Department uses its own ten-code system[14]
New Zealand's Fire Service uses a similar "K-code" system.[15]
The California Highway Patrol uses eleven-codes.[16]
Q code and prosigns for Morse code are used in amateur radio, aviation and marine radio. They provide specific abbreviations for concepts related to aviation, shipping, RTTY, radiotelegraph and amateur radio.[17] In radiotelegraph operation, a Q code is often shorter (as ten-codes require transmission of three prefix characters: 1, 0, hyphen) and provides standardization of codes, essential in international and shortwave communication.
Z codes are used by NATO countries in military radio communications.
Q: Our 911 center, which receives and dispatches emergency and non-emergency calls, has told us that we may not use 10-codes at all. I gather we must use plain language when using NIMS ICS. Am I correct?
A: Yes, when engaged using ICS, plain language is required. The value of using 10-codes for simplicity and speed is lost when others are confused, as may occur in a multi-jurisdiction/multi-agency response: the codes used in one jurisdiction or agency may not be the same in another. It is important that responders and incident managers use common terminology to prevent misunderstanding. While plain English is not required internally, it is encouraged over 10-codes to promote familiarity with emergency operational procedures.