#2: Headphone Jacks
We associate headphone jacks with modern technology, but this invention is actually much older than recent history. The modern headphone jack was invented and created in the late 1800s. How can that possibly be? They didn’t have car audio and music streaming back then! Well, the headphone jack, otherwise known as a phone connector, was invented for something we don’t use anymore.

The phone connector was invented for telephone switchboards. People of a certain age are probably wondering, “What’s that?” The jack and plug were developed and patented in the late 19th century to help different electronic devices connect with each other. Without the headphone jack, we wouldn’t have been able to develop early forms of telephone communication. Now, we use this technology for just about anything.