Cables and radio, on the same trip

Your phone has no wire. Yet its message soon travels through cables.

The wire-free part is usually just the first hop. A hop is one part of the trip. The box is a Wi-Fi box or a phone tower.

A message can travel in a cable. Long cables are thin glass threads that carry light. Or it can travel as a radio signal. Wi-Fi and mobile data use radio.

Rule: Radio carries the short first hop from a phone. Cables carry most of the rest.

Radio needs no wire. Radio lets a phone move around. But radio fades with distance. A phone too far from the box loses the first hop. Cables carry messages over long distances. Cables on the sea floor carry most data between continents.

Walk the phone away from the box. Find where the first hop breaks.

Try the lab to finish this lesson.