Copper cabling is most commonly referred to as Cat 5, Cat 6, etc. Copper cabling is most commonly used to run from each device (computer, printer) back to the MDF (main distribution facility). The Cat 5 drops have a plug in that appears to be a large telephone plug in. This end will plug directly in to most network cards on a computer or peripheral device on your network.
Copper can be used for both voice and data.