Copper cabling is one of the three types of physical media used for the transmission of information over data networks. The Physical Layer of the OSI Model defines the types of cabling used, and how information is encoded on to that cable. Copper cabling comes in many forms.

Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference. Data is transmitted on copper cables as electrical pulses.

Copper can't go the distance. The greater the distance between two points of copper cabling, the more noise it picks up and the greater the signal breaks down or degrades. This is good old copper attenuation at work, and it severely limits the size and scope of networks.