Unshielded twisted pair
Unshielded twisted pair (UTP) has no additional shielding to protect the medium from noise. UTP is classified into different categories or levels. The difference between the various categories is primarily the number of twists per meter of cable, although there are also differences in wire gauge. Generally the lower the category, the lower the cost and performance.
The primary disadvantage to UTP is its greater susceptibility to noise (compared to STP). This tends to limit its transmission rates and distance capabilities as compared to other wired media. That being said, advances in UTP have created increasingly higher level categories rated to higher and higher frequencies, which means they can be used for ever greater transmit rates. UTP is, without question, the LAN medium of choice.
|<mp3>http://podcast.hill-vt.com/podsnacks/2007q2/utp-stp.mp3%7Cdownload</mp3> | Unshielded twisted pair (UTP) vs. shielded twisted pair (STP)|