Application

• A greater issue of compatibility for the two cable types is the type of network each is intended to create. Cat-5 UTP was recommended for Fast Ethernet. This carried data at 100 megabits per second. Cat-5 is made any more, it was superseded by an improved version called Cat-5e, where the "e" stands for "enhanced." Cat-5e was recommended for Ethernet networks achieving data throughput of 1 gigabit per second. A gigabit is 1,000 megabits, or a thousand million bits. The performance of Cat-5 and Cat-5e cable was judged to be insufficient for higher grades of gigabit Ethernet. Cat-6 however, is recommended for use with 10 and 40 gigabit Ethernet networks.
  
  

Structure

• Both Cat-5 and Cat-6 are called "structured cable." This is because the cable holds a number of composite wires with a specific configuration. Unshielded twisted pair, or UTP, cable contains eight wires, grouped into four pairs. Each pair contains the positive and negative wires of a complete circuit. The two wires are twisted around each other for the length of the cable. Each wire is made of stranded copper wire and is coated in a color-coded plastic jacket. The color coding aides technicians to follow wiring plans.
  
  

Shielding

• Some cables contain a metal shield beneath the outer plastic covering. This is to protect the wires inside from magnetic interference. UTP cable does not need this shield. This is because, a current passing along a wire creates a magnetic field around that wire. The environmental magnetic interference merges with the magnetic fields around the wires. When the two wires in each pair are twisted around each other, the magnetic fields surrounding them merge. As they are of opposite polarity, this causes the two fields to cancel each other out, taking the absorbed environmental magnetic interference with them.
  
  

Future

• Cat-5 is still the most widely implemented for of network cable in the world today. However, as network administrators upgrade to faster networks, this predominance will fall. Cat-6 will not be the best form of UTP forever, the definition of Cat-7 is already under way by the Electronic Industries Alliance.