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Calling All Cars

Adam 12 sound byte

San Rafael PD Meter Maids c1973 Marie Morris, Sharon Bunker, Thonie Mulcahy (Hevron)
San Rafael PD Meter Maids c1973 Marie Morris, Sharon Bunker, Thonie Mulcahy (Hevron)

Back in 1973, when I first got hired as a Parking Enforcement Officer with San Rafael Police Department in California, I didn’t need to worry about 10 codes. For the first 2 years of my tenure, we had no radio in our “buggies”. Of course, I learned them anyway. Then around 1975, after a Hell’s Angel accosted me (it’s not what you think: I was on 4th Street–the main drag–and this Romeo decided he was irresistible and wouldn’t take NO for an answer). Because the incident occurred downtown in a highly visible area, merchants called the swamped police dispatch straightaway. Admin decided I needed a radio of my own way to call for help. The “portable” radio they gave me to use was about 8 pounds and 12” x 10” x 3”. Not so portable, really. Months later when was assigned to having cars towed from no parking zones, I had to really learn to talk on that darn thing. So using the only role model available–Adam 12–I wrote down what I needed to say on the radio, then read it with the mike keyed. I knew it wouldn’t take too long to learn the ins and outs–I was a quick study.

The radio was to become my career, even though I denied it to anyone who would listen. There have been high points and low points, to be sure. But learn it, I did.

One of the first things I had to learn was the 10-code, aka the aural brevity code. San Rafael Police Department–as do many municipalities in California–used the 10 code. The 9 code is a relic from years past sometimes used and the 11 code is primarily the California Highway Patrol’s realm. To be accurate, most agencies use a mix of the 10 and 11 codes.

Calling All Cars

Motorola has a great website to detailing the beginning of police radio communications.

The development of the 10-codes began in 1937, when police radio channels were limited, to reduce use of speech on the radio. Credit for inventing the codes goes to Charles “Charlie” Hopper, communications director for the Illinois State Police, in Pesotum, Il. Hopper realized there was a need to abbreviate transmissions on State Police bands.

Experienced radio operators knew the first syllable of a transmission was frequently not understood because of quirks in early electronics technology. Radios in the 1930s were based on vacuum tubes powered by a small motor-generator called a dynamotor. The dynamotor took from 1/10 to 1/4 of a second to “spin up” to full power. Police officers were trained to push the microphone button, then pause briefly before speaking; however, sometimes they would forget to wait. Preceding each code with “ten-” gave the radio transmitter time to reach full power.

Highway Patrol with Broderick Crawford
Highway Patrol with Broderick Crawford

Ten-codes, especially “ten-four”, first reached public recognition in the mid- to late-1950s through the popular television series Highway Patrol, with Broderick Crawford. Crawford would reach into his patrol car to use the microphone to answer a call and precede his response with “10-4”.

Ten-codes were adapted for use by CB radio enthusiasts during its pop culture explosion in the late 1970s. The hit 1975 song “Convoy” by C. W. McCall depicting conversation among CB-communicating truckers put phrases like 10-4 meaning “understood” and what’s your twenty? (10-20) for “where are you?” into common and use in American English. A 1978 movie Convoy, loosely based on the song, further entrenched ten-codes in casual conversation.

Replacement with plain language

As of 2011, ten-codes remain in common use, but have been phased out in some areas in favor of plain language. Nineteen states were planning to change to plain English as of the end of 2009.

10-4 does not mean “yes” (one of my pet peeves), only “understood” “acknowledged” or “ok”.

Official 10 codes

This link provides the standard published by Association of Public-Safety Communications Officials (APCO) list of 10 codes. However, each agency has its own peculiarities and codes often morph into something unique to the department. When I worked for Petaluma Police (1981-1992), the standard code for “station” (the police station) was “W”. I asked once what it stood for. No one could recall. I doubt they are still using this.

Codes are often used in a more abbreviated form. For instance, using Rohnert Park Department of Public Safety, an exchange that could be “4 Sam 1, 10-20?” “First and Main” might be more like “4 Sam 1, what’s your 10-20?” “My 20 is First and Main”—it would be more efficient to simply ask, “4 Sam 1, where are you?” “I’m at First and Main.” FYI: The “4” before the “Sam” in the call sign denotes the agency. In Sonoma County, “1” stands for Sonoma County Sheriff’s Department. Surrounding agencies are numbered by mutual agreement and use their numbers in their department call signs. The “Sam” is a rank designator, in this case a sergeant.

  • “Lincoln” is a patrol officer
  • “Tom” is a traffic officer
  • “Mary” is a motor officer
  • “David” is a detective
  • “Adam” is an administrator

The number following is called the “unit number” and generally assigned by seniority. For instance, the most senior patrol officer would be “4L1” or “4Lincoln1”.

Just so you don’t think this cop stuff is too easy, there are agencies who adjust an officer’s call sign by shift, beat or zone and unit. For instance, Sonoma County Sheriff uses this system: “E-Edward” is a dayshift unit, “F” is swing (afternoons) shift, and “G” is graveyard (nights). The agency designator stays the same but if an officer is hired for overtime and works a different shift than normal, he has to learn to say his correct radio call sign. In times of intense stress, this has proven to be problematic.

On the other hand, there are times when the use of codes is appropriate, even if less efficient than speaking “clear text”. 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 plain-speech terms for the trauma.

Incident Command System at work
Incident Command System at work

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. An example: in Marin County, a “code 6” is a warrant check. In Sonoma County, it is a request for back-up. Yikes.

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. 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. The New Orleans Police Department continued using 10-codes as of 2010.

There is no easy answer. Besides codes, clear talk is the only other option. Yet there are times when law enforcement agencies need expeditious codes. Standardization is a great idea but as long as more than two agencies are involved, there will be differences.

Next, some interesting thoughts from a friend who moved from a California fire agency to a Mid-west military installation. The next post will be guest Elaine O’Brien from Fort Riley PD. You’ll love some of her insights!

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