Since its invention, communications technology has always depended on some form of telecommunications infrastructure. In this instance, infrastructure refers to a network of processing centers and devices designed to send electronic signals from one location to another. Early forms of telecommunications infrastructure depended on wires and cables that had to be physically strung to any location, no matter how remote. Modern infrastructure increasingly utilizes wireless technology that communicates with satellites, signal towers, or small, local devices in a home or business.
Before the advent of electronic communications, any message sent to a distant location had to be delivered by hand, a process that involved great time and expense. Public and private postal services were aided by innovative approaches such as semaphore signs, light beacons, or even smoke signals. Each of these methods required an infrastructure, a preexisting network set up to process and deliver messages. When the telegraph was invented in the 1830s, it too required an infrastructure, a network of wires to communicate the telegraph signal. By the 1860s, telegraph cables, the first telecommunications infrastructure, had been placed in various nations around the world.
The telegraph allowed messages to be delivered one letter at a time over great distances using methods such as Morse code. The telegraph was superseded by the invention of the telephone in the 1870s, but the idea behind telecommunications infrastructure remains unchanged, even in the 21st century. Even though the telephone could relay voice information almost instantly over great distances, it still required an infrastructure of wires, cables, and human operators. In the 1950s, ships installed underwater telephone cables linking the continents, an engineering feat that created the first truly global telecommunications infrastructure.
As telephone technology has advanced over the decades, simple electronic wires have been replaced with fiber-optic cables. These can communicate more information faster, using light rather than electricity as the medium for transmitting the signal. This allowed the widespread use of facsimile, or fax, machines that could transmit documents over phone lines. Once a worldwide telecommunications infrastructure had been established with fiber-optic cables, the Internet became a possibility. Computer networks used existing phone lines to transmit not just text and images, but video, commerce, and complicated interactive websites.
In the 21st century, telecommunications infrastructure includes cell phones that can transmit signal wirelessly to satellites in space, as long as they are within distance of a relay tower. Relay towers have been erected all over the world, allowing a device the size of a credit card to communicate with any other phone, anywhere on Earth. Wi-Fi infrastructure allows Internet-ready computers to have roughly the same coverage without being directly connected to phone lines. They can instead communicate wirelessly with Wi-Fi transmitters located in many businesses, homes, and even remote, formerly inaccessible locations, such as the peak of Mount Everest.