What is Thick Ethernet?

Thick Ethernet was the first commercially available form of cabling supported by Ethernet. It is technically known as 10BASE-5, where 10 represents the maximum throughput of 10 Mbps, BASE denotes the use of baseband transmission, and 5 refers to the maximum segment length of 500 meters (1,640 ft).

This type of cabling allows up to 100 stations to be connected using vampire taps, which are special connectors that pierce the cable to establish electrical contact. All stations share a single collision domain, meaning only one device can transmit at a time to avoid data collisions.

Cable Structure

The coaxial cable used in thick Ethernet is 0.5 inches (12.7 mm) in diameter and typically has a distinctive yellow outer PVC coating. It is a low-loss 50-ohm impedance cable that is somewhat inflexible due to its robust construction.

The cable consists of four main components:

• Inner conductor − A solid copper wire core that carries the electrical signals

• Dielectric insulation − Insulating material surrounding the inner conductor

• Braided shield − Woven metal mesh that provides protection against electromagnetic interference

• Outer jacket − Yellow PVC coating that protects the cable from environmental damage

Network Design

Thick Ethernet uses a bus topology where the 10BASE-5 coaxial cable forms the shared communication medium. The network design includes several key components:

• Vampire taps − Special connectors that pierce the cable without cutting it to establish electrical contact

• AUI cables − Attachment Unit Interface cables connect stations to the vampire taps (maximum 50 meters)

• Terminators − 50-ohm resistors placed at both ends of the cable to prevent signal reflections

• Maximum segment length − 500 meters without repeaters

Advantages and Disadvantages

Conclusion

Thick Ethernet (10BASE-5) was the pioneering Ethernet technology that used robust coaxial cables to create reliable networks. While it provided excellent performance and noise immunity, its high cost and installation complexity led to its replacement by more flexible and cost-effective solutions like twisted-pair cabling.