Ethernet Cables

Ethernet Cables

CAT5 Ethernet Cable
This is inexpensive unshielded twisted pair (UTP) data grade cable, but for industrial control you have to get the shielded twisted pair (STP) cable. It is very similar to ubiquitous telephone cable but the pairs are more tightly twisted. Fast Ethernet carried over CAT5 cable is known as 100BASE-TX. A CAT5 cable usually contains four twisted data pairs of which two are actually used by Ethernet; one pair for transmit and one for receive.

Newer "class 6 or 7" cables such as Belden MediaTwist 1872A have even better performance than CAT5 cable. These newer cable types have less loss and crosstalk within the cable and are more immune to interference from outside sources.

Fiber Optic Cable
Fiber optic cable offers two main advantages over twisted pair cable. First, data may be carried much further over fiber. Second, fiber is immune to electromagnetic interference.

There are two basic types of fiber in use today: Multimode and Single Mode. Multimode fiber is used extensively in the data communications industry. Fast Ethernet carried over multimode fiber is known as 100BASE-FX. Ethernet may be carried up to 2 kilometers on this fiber. Single mode fiber is used extensively in the telecom industry. Single mode fiber allows much greater run lengths than multimode fiber. Although there is no official standard for carrying Ethernet over single mode fiber, numerous datacom products offer this capability

Crossover Cable
A crossover cable can be used to directly connect two network devices, hubs or switches. A crossover cable is a CAT5 cable wired such that the transmit data pair at one end is connected to the receive data pair at the other.