Gorry Fairhurst - Date: 01/10/2001 EG3557

Thin Ethernet (10B2 / IEEE 802.3a)

One form of cabling supported by Ethernet is low cost 50 Ohm coaxial cable as shown in the figure below. This type of cable is cheap to purchase and is flexible and easy to install. It has become known in the communications industry as "Thin Ethernet", so called to differentiate it to "Thick Ethernet" which was originally used in Ethernet LANs. The official name for this cable is 10 Baseband2 (10B2), indicating that it is specified for baseband communications (i.e. not modulated) at 10 Mbps over distances up to approximately 200m.

10B2 Cable or "Thin Ethernet"

The connection of a network interface card in a computer to 10B2 cabling is usually via a BNC connector as shown in the figure below. Some buildings use a special type of connector in place of the more common BNC to try to prevent problems arising when users disconnect or reconnect their equipment. (This may otherwise cause a break in the transmission medium inhibiting communication between other users.) The end of each segment of cable must be terminated with a 50 Ohm BNC terminator.

Connection of transceiver on equipment to a 10B2 Ethernet network

10B2 cabling is flexible and the network may be constructed in any convenient way by simply connecting all devices to the cable (see below).

A typical cabling scheme for 10B2 cabling in an office

A summary of the properties of this type of cabling is given below: