ELI5: Explain Like I'm 5

End-of-Transmission character

An end-of-transmission character (also known as ETX) is a small symbol that tells computers when a message is finished being sent. When you send a message on a computer, it's like you're sending a letter. An end-of-transmission character is like a period at the end of your sentence.

Imagine you are writing a letter to your friend using a computer. You type out your message and then hit "send." When you hit "send," the computer takes all the letters you wrote and sends them through the internet to your friend's computer. But how does your friend's computer know when your message ends and the next one begins? That's where the end-of-transmission character comes in. It tells your friend's computer when your message is finished, so the computer won't keep waiting for more letters to come.

The end-of-transmission character is just a tiny symbol, usually represented by the number 3 or the character "^C". When your computer sends this symbol, it tells the receiving computer that it has finished sending the message. This is really important when you're sending and receiving a lot of data, like when you're downloading a big file or streaming a movie. Without the end-of-transmission character, computers wouldn't know when to expect the next bit of information, and things could get really confusing! So, the end-of-transmission character makes sure that messages are sent and received correctly.
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