Ethernet Cabling

• 10 Base 5, or Thicknet, uses a single 75-ohm coaxial cable in a bus topography, connecting each device with a "vampire tap" clamped over a hole drilled in the cable. Segments may be up to 500 meters in length. Not recommended for new installations.

• 10 Base 2, or Thinnet, uses a string of RJ-58 coaxial cables in a bus topography, with BNC T connectors attached to each device, and 52-ohm terminators at each end. Maximum segment length is 200 meters.

• 10 Base T uses twisted pair wiring (preferably shielded) in a star topography, with each segment connecting a single device to a repeater, usually referred to as a hub. Unlike other Ethernet cabling schemes, which specify physical cable types, 10-Base-T specifies requirements for various electrical properties of the wiring. The only reliable way to meet these requirments is by checking wiring with a cable tester, an essential tool for large 10-Base-T installations.

• 10 Broad 36, the only broadband Ethernet design, permits operation over closed-circuit cable television systems, requiring three adjacent TV channels to be allocated for a single Ethernet segment.

• Fiber optic Ethernet segments have been developed by several companies, though there is no fiber standard to my knowledge.

Ethernet segments can be interconnected using repeaters, bridges (see bridging concepts), and/or routers (see routing concepts).