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What’s The Difference Between “10-4”, “Roger”, And “Copy” In Radio Language? (Detailed)

What’s The Difference Between “10-4”, “Roger”, And “Copy” In Radio Language? (Detailed)

Military radio language is one of the military’s most complex and fascinating elements. It’s a system that requires specialized training to use effectively.

Because military radio language is so complex, you must understand what it is and how it works before you start using it yourself. This will help you avoid mistakes that could damage your communication with other units or even get you in danger.

These codes include words like 10-4, roger, and copy.

10-4 is short for “10-4, good buddy.” It is used to confirm a message and can be used in response to any message.

Roger is short for “roger that.” It is used to acknowledge a message and can be used only in response to a message previously sent by the person doing the acknowledgment.

Copy is short for “I copied your last transmission.” It is used to acknowledge a message and can be used only in response to a message previously sent by the person doing the acknowledgment.

Let’s dive into the details of radio language.

What’s Meant By “10-4” In Radio Language?

10-4 is a radio term to acknowledge that you received a message. It means “yes,” or “I agree.”

The phrase originated in the 19th century when there was no formalized communication system between police officers and other emergency services. If someone wanted to let the other party know they had received their message, they would say 10-4. The word 10 referred to their location, while the word 4 meant “received” or “understood.”

In modern times, this term has expanded beyond its origins. It can be used by anyone who wants to inform another person that they have understood something or agree with what has been said.

An image of a radio communication set.
Emergency radio communication set

What’s Meant By “Roger” In Radio Language?

When you hear the word “roger,” your radio operator has received your message and understands what you’re saying.

The origin of “roger” is unclear. Some say it’s derived from the Latin word “rogare,” meaning “to ask.” Others say it comes from a 19th-century British sailing term: when a ship would see another ship coming in their direction, they would use flags to communicate with one another. When the other ship saw their flag, they would respond with a flag bearing the letters R-O-G-E-R.

In radio transmissions, roger is often used to acknowledge that a message has been received and understood. For example:

  • An airplane pilot might say: “This is [airplane name].
  • Do you copy?” (meaning: Do you understand me?) and the ground crew at an airport might respond: “Roger that.”
  • A military commander can say: “We need reinforcements at [location].”

What’s Meant By “Copy” In Radio Language?

Copy is a word used in radio language to indicate that you have received the message. It can be used to express agreement or understanding, or it can be used to acknowledge that you have received information from another person.

When someone says “copy that,” it means that they agree with what was said or that they understand what was said and will use the information provided. For example, if someone says: “Copy that,” this indicates that they have understood what was said and will act accordingly.

It can also be used to acknowledge that something has been sent to you over the radio, like when someone says: “Copy that.” This would mean they acknowledge receipt of a message sent by another person over the radio.

What’s The Difference Between 10-4, Roger, And Copy?

Roger, 10-4, and copy are the words used for communication in radio language. Although all these words have the same meanings, they are slightly different.

  • 10-4 is a general acknowledgment of transmission, but it does not necessarily mean you understand it.
  • Roger means you understand the transmission.
  • Copy is used to confirm that you have received an entire group of transmissions.
An image of a radio set.
Wireless communication radio used by traffic police

10-4 vs. Roger vs. Copy

Let’s get to know the differences in a bit of detail now:

10-4

10-4 is used to acknowledge another person’s statement. It means “acknowledged.” For example: “Yes, I understand you have a question.”

10-4 is a confirmation of understanding. It means “yes,” but it’s more of a way to confirm that you heard the other person’s words and understand what they mean.

Roger

Roger is also used to acknowledge another person’s statement. However, it means “received” or “understood.” For example: “Yes, I received your last transmission.”

Roger is 10-4, but it’s used in a situation where the person on the other end of the radio isn’t sure if they heard correctly or not. So if someone says “Copy?” and you are not sure what they meant, you can say “Roger” to let them know that you hear them correctly.

Copy

Copy is also used to acknowledge another person’s statement. However, it means “I understand you” or “I agree with what you said.” For example: “Yes, I got your last message loud and clear.”

Copy is a simple way to acknowledge that you’ve heard what someone has said without giving further information about your comprehension of the message—it’s just one word. It doesn’t require further explanation or clarification from either party involved in the conversation.

WordsLong-FormMeaning
10-410-fourI understand.
RogerReceived or roger thatI understand.
CopyReceived or copy thatI understand.
Words used in radio language

Why Do Soldiers Say “Copy?”

Soldiers use the word copy to mean that they understand and will follow a command. It can also acknowledge a message or say that an order has been received and understood.

The term came into common usage in the military during World War I, when radio operators would repeat back what they heard over their radios so that their commanders could verify it was correct.

Why Do People Use “Roger that?”

People use “Roger that” in radio communication to get confirmation from the other person that they’ve heard what was said.

It’s a way of saying “I understand” or “I agree,” and it can also be used as a way to acknowledge that you’ve received information—such as when you’re asked for your name, and you reply, “Roger.”

What Is A Response To “10-4?”

A 10-4 response indicates that you understand a message or have received it. It is also used to show that you agree with the message.

The full response is “10-4.” The “10” stands for “Over,” and the “4” stands for “Roger.” When responding to a 10-4 message, you should say only “10-4.”

How Do You Speak To Military Radio?

To speak to a military radio, you must first establish your call sign and station. These are given to you by your commanding officer. Once you have those, you can begin speaking.

Here is a short video clip telling you how to use a military radio.

To start speaking on the military radio, say “this is,” followed by your call sign and station name. If you do not have one yet, say “this is,” followed by your name or a nickname if you have one.

You can then give your message in any way that makes sense—you could say it as a question (for example: “this is Joe calling from base camp“) or as a statement (for example: “I am at base camp”). After giving your message, wait for an acknowledgment signal before ending the conversation.

Final Thoughts

  • The radio language operators use three common phrases: 10-4, roger, and copy.
  • 10-4 is an acknowledgment that the message has been received, but it is not a confirmation. It can also be used to affirm that the message was understood.
  • Roger is a confirmation of a message. The speaker uses this when they have received and understood the message.
  • Copy is a request for affirmation from another person that they have heard what was said on their end of the conversation.

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