Connectors for Coaxial Cable

Connectors for Coaxial Cable

Two types of connectors are commonly used with coaxial cable. The most common is the British Naval Connector (BNC). Figure 3.8 depicts the following characteristics of BNC connectors and Thinnet cabling:

A BNC T-connector connects the network board in the PC to the network. The T-connector attaches directly to the network board.
BNC cable connectors attach cable segments to the T-connectors.
A BNC barrel connector connects to Thinnet cables.
Both ends of the cable must be terminated. A BNC terminator is a special connector that includes a resistor that is carefully matched to the characteristics of the cable system.
One of the terminators must be grounded. A wire from the connector is attached to a grounded point, such as the center screw of a grounded electrical outlet.

In contrast, Thicknet uses N-connectors, which screw on instead of using a twist-lock (see Figure 3.9). As with Thinnet, both ends of the cable must be terminated, and one end must be grounded.

Workstations don’t connect directly to the cable with Thicknet. Instead, a connecting device called a transceiver is attached to the Thicknet cable. This transceiver has a port for an AUI connector, and an AUI cable (also called a transceiver cable or a drop cable) connects the workstation to the Thicknet medium. Transceivers can connect to Thicknet cables in the following two ways:

Transceivers can connect by cutting the cable and using N-connectors and a T-connector on the transceiver. As a result, the original method now is used rather infrequently.
The more common approach is to use a clamp-on trans-ceiver, which has pins that penetrate the cable without the need for cutting it. Because clamp-on transceivers force sharp teeth into the cable, they frequently are referred to as vampire taps.

You can use a transceiver to connect a Thinnet LAN to a Thicknet backbone.

AUI port connectors sometimes are called DIX connectors or DB-15 connectors.