Ground start trunk

Have you ever seen a telephone booth? Inside the booth are phones that you can use to call people. But did you know that the phone in the booth can also be used to call someone outside the booth?

Well, to make this happen, you need something called a ground start trunk. A trunk is like a big pipe that connects two phone systems together.

Now, let's try to explain how a ground start trunk works. Imagine two people, Person A and Person B, who want to talk to each other on the phone. Person A is inside the telephone booth, and Person B is outside.

Person A picks up the phone inside the booth and presses a button. This sends a signal to the phone company's equipment, telling it to connect Person A's phone to Person B's phone.

When that signal reaches the phone company's equipment, it sends a special sound down the trunk to Person B's phone. This special sound is like a knock on Person B's phone's door.

When Person B's phone hears the knock, it knows that someone wants to talk, so it picks up the call automatically. And that's how Person A and Person B can talk to each other on the phone, using a ground start trunk!