Still trying to figure out the technology behind sending a fax? Fiber-optic cable will give you something else to think about. Fiber-optic cable is made out of incredibly pure glass that’s as thick as a strand of hair. It’s coated in 2 layers of reflective plastic. A light source (usually a laser) travels through the glass strands and continuously reflects off of the inside of the mirrored plastic coatings to transmit digital data.
Systems based on fiber optics can transmit billions of bits of data per second, and they can even carry multiple signals along the same fiber by using lasers of different colors.