What Are the Main Cable Types in Computer Networks?

TL;DR

Computer networks connect devices using unshielded twisted pair, shielded twisted pair, coaxial, and fibre optic cables. Twisted pair and coaxial cables carry electrical signals, while fibre optic cable carries light signals. Cable notation identifies transmission rate, signaling mode, and supported distance, while attenuation explains why a signal weakens after traveling beyond a cable’s specified range.

Transcript

Hello friends, Welcome to Gate Smashers in today’s video we are going to discuss about cables. So in computer networks we use different types of cables and why we use them generally? To connect various devices, here we have different types of cables unshielded twisted pair cable, coaxial cable, shielded twisted pair cable or fibre optics. The names... Read More

Key Insights

• Network cables are physical media that connect devices and carry packets or data as signals. The main types discussed are unshielded twisted pair, shielded twisted pair, coaxial, and fibre optic cable, each supporting network communication through its own signaling characteristics.
• The number in 10BASE-T is a transmission rate of 10 megabits per second. Bandwidth describes how many bits can be transmitted each second, while 100BASE-T represents a higher transmission rate of 100 megabits per second.
• Baseband transmission allows only one signal to use the wire at a time. If another device transmits simultaneously, the signals can collide, so a sender and receiver using this shared medium must communicate at different times.
• The T in 10BASE-T corresponds to a supported cable distance of 100 meters. Unshielded twisted pair carries electrical signals, and attenuation weakens the signal after that distance until its remaining energy is insufficient for continued transmission.
• Coaxial cable carries electrical signals and supports longer example distances than 10BASE-T. In the presented notation, 10BASE-2 corresponds to 200 meters, while 10BASE-5 corresponds to 500 meters before attenuation limits further signal travel.
• Fibre optic cable transmits light rather than electrical signals. The light signal travels at 3 x 10^8 meters per second, and 100BASE-FX provides 100 Mbps baseband transmission over a fibre channel for approximately 1.9 kilometers, or about 2 kilometers.
• The maximum number of devices participating in a collision can equal the total number of connected devices, n. This occurs when all n devices begin transmitting simultaneously on a shared baseband wire, causing their signals to collide.
• Cables operate at the OSI physical layer and cannot filter network traffic. They are pure hardware without software, so they cannot inspect IP addresses or MAC addresses or decide whether a signal should continue between connected LANs.

Questions & Answers

Q: What types of cables are used in computer networks?

Computer networks use unshielded twisted pair, shielded twisted pair, coaxial, and fibre optic cables to connect devices and carry data. Unshielded twisted pair and coaxial cables transmit data through electrical signals. Fibre optic cable instead carries light signals. These cables serve as communication media in networks, including Ethernet local area networks used within offices and organizations.

Q: What does 10BASE-T mean in computer networking?

In 10BASE-T, 10 represents a bandwidth of 10 megabits per second, meaning that 10 megabits of data can be transmitted in one second. BASE identifies baseband operation, where only one signal can transmit on the medium at a time. T corresponds to a cable distance of 100 meters, after which signal attenuation becomes significant.

Q: What is the difference between baseband and broadband transmission?

Baseband transmission permits only one signal to travel through a wire at a time. If another device sends a signal simultaneously, a collision can occur. Broadband transmission allows multiple signals to move in parallel. With the baseband arrangement described, a sender and receiver can communicate in both directions at different times, but not simultaneously on the shared medium.

Q: What is attenuation in a network cable?

Attenuation is the reduction of a signal’s strength or energy as it travels through a cable. Once the signal passes the distance specified for the cable type, it becomes too weak to continue effectively. The examples given are 100 meters for 10BASE-T, 200 meters for 10BASE-2, 500 meters for 10BASE-5, and approximately 2 kilometers for 100BASE-FX.

Q: How do twisted pair and coaxial cable differ in supported distance?

The unshielded twisted pair example 10BASE-T supports electrical signal transmission for 100 meters before attenuation limits the signal. The coaxial examples cover longer distances: 10BASE-2 corresponds to 200 meters, and 10BASE-5 corresponds to 500 meters. In each case, the signal weakens after the indicated distance and cannot continue traveling effectively without further support.

Q: How does fibre optic cable transmit network data?

Fibre optic cable carries data using light signals instead of the electrical signals used by twisted pair and coaxial cables. The stated speed of the light signal is 3 x 10^8 meters per second. In the 100BASE-FX example, the cable supports 100 Mbps baseband transmission through a fibre channel for about 1.9 kilometers, approximately 2 kilometers.

Q: How many devices can participate in a cable collision?

If n devices share a baseband wire, the maximum number that can participate in a collision is n. This maximum occurs when every connected device starts transmitting at the same time. Because baseband permits only one signal on the medium at a time, all simultaneously transmitted signals collide, creating a shared collision domain involving every connected device.

Q: Which OSI layer do network cables operate at?

Network cables operate at the OSI physical layer because their basic purpose is to provide a connection and carry signals. A cable is pure hardware and contains no software for examining network information. It cannot inspect IP addresses or MAC addresses, filter traffic, or decide whether a signal should proceed from one connected LAN to another.

Summary & Key Takeaways

• Computer networks use cables as physical media for connecting devices and transmitting packets as signals. The discussed types are unshielded twisted pair, shielded twisted pair, coaxial, and fibre optic cable. Twisted pair and coaxial media transmit electrical signals, whereas fibre optic media transmit light signals at 3 x 10^8 meters per second.

• Ethernet labels communicate cable capabilities. In 10BASE-T, 10 represents 10 Mbps, BASE indicates baseband transmission, and T corresponds to a 100-meter distance. The 100BASE-T form increases the transmission rate to 100 Mbps. Coaxial examples include 10BASE-2 for 200 meters and 10BASE-5 for 500 meters.

• Cables operate at the OSI physical layer and provide basic connectivity without inspecting IP addresses or MAC addresses. They cannot filter traffic because they contain no software. Signal strength declines through attenuation after a specified distance, and collisions are possible when multiple devices transmit simultaneously over a shared baseband medium.