Ask Dr. Universe: Before cellphones, how did you make calls across the ocean?

Dr. Universe: Back when cellphones weren’t a thing, how could you place a call from across the ocean? Were there wires under the ocean? – Tali, 9, Seattle

Dear Tali,

Long before telephones, if you wanted to say “hi” to friends across the ocean, you’d probably write them a letter and send it over on a ship.

But in the last hundred years or so, we’ve been able to connect across the ocean much faster. And, yes, it often required thousands of miles of wires, or cables, deep in the sea.

That’s what I found out from my friend Bob Olsen, a professor of electrical engineering at Washington State University, who told me all about the telephone.

The telephone helps translate the sound waves from your voice into electrical signals. Those electrical signals can flow through cables on land, and, as you hypothesized, under the ocean.

Before there were cellphones, we made calls on a landline. It was a kind of phone with copper wires that flowed from your phone, into the wall and on to a phone company’s central office.

When you’d dial a long-distance number, a lot of things started happening behind the scenes.

After you dialed the number, someone at the phone company’s central office would get your call. At the office, that person would help switch the call, or move the right wires around, to connect you with their long-distance office.

The person at the long-distance office would connect your call to the phone company office nearest to your friend’s house. The wires on land and the cables beneath the ocean helped this message travel in the form of electrical signals.

While we used to depend on people to help make the switches, now computers can do it. As engineers came up with new ideas about telephones, they also learned that they could use satellites to help these signals travel long distances. Instead of using long-distance cables, a call goes up to a satellite and bounces back down to your friend.

Olsen said he remembers calling his uncle who lived across the country once a year. It was a special occasion, and all of the kids in his family would line up to just say “hello.” It was very expensive to make a long-distance call. Maybe you can ask your parents or grandparents about it.

Even though a lot of people now use wireless phones rather than landlines to connect with each other, we still depend on those wires under the ocean for long-distance phone calls. The old wires have now been replaced with optical fibers that are a much better way to send these signals. We also depend on them for one big thing many of us use every day: internet.

When we search the web, make a video call or send texts from an app overseas, that information in the form of electrical signals is flowing deep beneath the ocean on optical fiber cables. You can check out the map at www.submarinecablemap.com to see how the cables work and are all connected.

The next time I go to the ocean or call a friend, I’m going to remember the important work electrical engineers do to help us all stay connected – and let me answer great questions from kids like you.

Sincerely,

Dr. Universe