Glossary of Cables

Also referred to as Coaxial, Thinnet, 10base2, and RG 58 Cable.

BNC cable is used to connect two or more of your computers to share files and printers, etc.. You will need a BNC Network card for each computer. You will also need two BNC T's (these usually come with the cards) and two terminators (these do not come with the cards).

You must attach a T and a terminator to each of the end computers in order for the computer to know you are running a BNC network, otherwise, it will not see the card.

There are basically two types of BNC connectors, twist-on and crimp on. This refers to the way the connector is mated to the coax cable.

Twist on RG58 BNC Connector	Crimp on RG58 BNC Connector

The transceiver is used to connect your existing Thick Ethernet Adapter card to a 10Base-T Ethernet Network utilizing Unshielded Twisted Pair cables.

UTP Cable vs STP Cable
Two copper wires, each encased in its own color-coded insulation, are twisted together to form a twisted pair. Multiple twisted pairs are packaged in an outer sheath, or jacket, to form twisted-pair cable. By varying the length of the twists in nearby pairs, the possibility of interference between pairs in the same cable sheath can be minimized.

Twisted-pair cable has been around for a while. In fact, early telephone signals were sent over a type of twisted-pair cable, and just about every building today still uses twisted-pair cable to carry telephone and other signals. However, signals have become more complex over the years, evolving from 1200 bps to over 100 Mbps. And there are many more sources of interference that might disrupt those signals today than there were at the turn of the century. Coaxial cable and fiber optic cable were developed to handle higher-bandwidth applications, and to support emerging technologies. But twisted-pair cable, too, has evolved so that it can now carry high-data-rate signals.

Some twisted-pair cables contain a metal shield to reduce the potential for electromagnetic interference (EMI). EMI is caused by signals from other sources such as electric motors, power lines, high-power radio and radar signals in the vicinity that may cause disruptions or interference, called noise. Shielded twisted-pair (STP) cable encases the signal-carrying wires in a conducting shield. At first glance, it may appear that because STP cable is physically encased in a shield, all outside interference is automatically blocked; however, this is not true.

Just like a wire, the shield acts as an antenna, converting received noise into current flowing in the shield when it has been properly grounded. This current, in turn, induces an equal and opposite current flowing in the twisted pairs. As long as the two currents are symmetrical, they cancel each other out and deliver no net noise to the receiver. However, any discontinuity in the shield or other asymmetry between the current in the shield and the current in the twisted pairs is interpreted as noise. STP cable is only effective at preventing radiation or blocking interference as long as the entire end-to-end link is shielded and properly grounded. To work properly, every component of a shielded cabling system must be just that fully shielded.

STP cable also has drawbacks; for example, its attenuation may increase at high frequencies, and its balance (or longitudinal conversion loss) may decrease if the effects of the shield are not compensated for, which leads to crosstalk and signal noise. The shielding effectiveness depends on the material of the shield, its thickness, the type of EMI noise field, its frequency, the distance from the noise source to the shield, any shield discontinuity, and the grounding structure used. Nor can it always be guaranteed that the shield itself will contain no imperfections.

Some STP cables use a thick braided shield. These cables are heavier, thicker, and harder to install than their UTP counterparts. Some STP cables only use a relatively thin overall outer foil shield. These cables, called screened twisted-pair (ScTP) cables or foil twisted-pair (FTP) cables, are thinner and less expensive than braided STP cable. However, they are not any easier to install the minimum bending radius and maximum pulling tension force must be rigidly observed when these cables are installed; otherwise, the shield may experience a tear.

Unshielded twisted-pair (UTP) cable, on the other hand, does not rely on physical shielding to block interference, but on balancing and filtering techniques through media filters and/or baluns. Noise is induced equally on two conductors, which cancels out at the receiver. With properly designed and manufactured UTP cable, this technique is easier to maintain than the shielding continuity and grounding of an STP cable.

UTP cable has evolved over the years, and different varieties are available for different needs. Basic telephone cable, also known as direct-inside wire (or DIW), is still available. Improvements over the years, such as variations in the twists or in individual wire sheaths or overall cable jackets, have led to the development of EIA/TIA-568 standard-compliant Category 3 (for specifications on signal bandwidth up to 16 MHz), Category 4 (for specifications on signal bandwidth up to 20 MHz), and Category 5 (for specifications on signal bandwidth up to 100 MHz and greater) UTP cable. Because UTP cable is lightweight, thin, and flexible, as well as versatile, reliable, and inexpensive, millions of nodes have been and continue to be wired with UTP cable, even for high-data-rate applications. For the best performance, UTP cable should be used as part of a well engineered structured cabling system.

RJ-45 vs. RJ-11 - RJ45 is usually cat3 or cat5 Twisted pair, RJ-11 is flat cable that is used for telephones.


SC connectors are specially designed for CATV and network applications and are fully compatible with existing SC hardware	ST fiber connectors are specially designed for distribution applications and are fully compatible with existing ST hardware

FDDI Duplex Connector - the FDDI connector is otherwise known as the MIC fibre connector.