STP stands for Shielded Twisted Pair.
UTP stands for Unshielded Twisted Pair.
The Institute of Electrical and Electronics Engineers (IEEE).
Relatively large core diameter; carry multiple modes of light; less expensive than single-mode fibre; can only be used for shorter distances (up to about 250m).
Small core diameter; carries a single mode of light; relatively expensive; capable of transmitting data over long distances (up to about 5km).