Network Cabling Guide: Types, Categories, and Connectors

Posted on May 15, 2024 in Technology

How to Generate a Null Modem

To create a null modem cable, you need to connect the following pins between connector A and connector B:

  • Pin 3 of connector A to pin 2 of connector B
  • Pin 2 of connector A to pin 3 of connector B
  • Pin 5 of connector A to pin 5 of connector B

Bypass pins 4, 6, and 1 on both connector A and connector B. Also, bypass pins 7 and 8 on both connectors.

Types of Transmission Media

Guided Media:

  • Twisted Pair
  • Coaxial
  • Fiber Optic

Unguided Media:

  • Radio Links
  • Satellites

Difference Between UTP and STP

UTP (Unshielded Twisted Pair): This cable has eight wires forming four twisted pairs without any shielding. It is less expensive than STP but offers lower performance.

STP (Shielded Twisted Pair): In STP, the wires are twisted in pairs, and each pair is covered by a metal layer for shielding. This shielding makes STP more expensive than UTP but allows it to surpass 100Mbps speeds.

Cable Categories

Cable categories define the standards that must be met in the final construction of the wiring. These categories determine the cable’s performance characteristics.

Velocities of Each Category

  • Category 1: (Not commonly used)
  • Category 2: Supports up to 4 Mbps
  • Category 3: Transmission speed of 16MHz, supports up to 10Mbps
  • Category 4: Supports up to 20 Mbps
  • Category 5: Transmission speed of 100MHz, supports up to 100Mbps
  • Category 5e: Transmission speed of 100MHz, supports 100Mbps, ATM 155 Mbps, ATM 622 Mbps, and Gigabit Ethernet
  • Category 6: Transmission speed of 250MHz, supports up to 1Gbps
  • Category 7: Not considered (used in Europe)

Purpose of Braiding

Braiding in cables helps improve resistance to external interference, ensuring signal integrity.

Cable Testing Parameters

Common cable testing parameters include:

  • Wire Map (Wiring Diagram)
  • Length
  • Attenuation
  • NEXT (Near End Crosstalk)
  • ACR (Attenuation Crosstalk Ratio)
  • Delay/Delay Skew (Delay/Delay Group)
  • Return Loss
  • Far End Crosstalk (FEXT)

Structured Cabling

Structured cabling is the wiring system of a building or a series of interconnected buildings that allows active equipment of different or the same technology to integrate various services like data, telephony, and monitoring.

Advantages of Structured Cabling

Structured cabling can support various communication services simultaneously, providing flexibility and scalability.

Patch Panel, Patch Cord, and User Outlet

Patch Panel: An electronic panel used in a computer network where all network cables terminate. It serves as a central point for managing network connections.

Patch Cord: A cable (UTP, fiber optic, etc.) used to connect electronic devices within a network. They come in various colors for easy identification and lengths to suit different needs. Longer patch cords may have shielding (STP) to prevent signal loss and interference.

User Outlet: A wall-mounted chassis where one or more computers connect to the network via a rosette.

Horizontal and Vertical Cabling

Horizontal Cabling: Cabling that runs from the floor distributor to the user outlets.

Vertical Cabling: Cabling that connects floor distributors to the main distribution frame (MDF) or other central points in the building.

EIA/TIA 586 A and B Standards

These standards define the color coding for twisted-pair cabling. They differ in the order of the colors used for the wire pairs in RJ-45 connectors.

Distance and Speed on Twisted-Pair Ethernet

  • 10BASE-T: Speed: 10Mbps, Distance: 100m
  • 100BASE-T4: Speed: 100Mbps, Distance: 100m
  • 100BASE-TX: Speed: 100Mbps, Distance: 100m
  • 1000BASE-T: Speed: 1000Mbps, Distance: 100m

Coaxial Cable Structure

Coaxial cable consists of:

  • A solid copper core or copper-coated steel, or a series of woven copper wire strands (depending on the manufacturer)
  • An insulating layer covering the core, usually made of polyvinyl material
  • A metal shield layer, typically woven copper or aluminum alloy, designed to eliminate interference
  • A final coating layer, usually black (thin coax) or yellow (thick coax), made of vinyl, polyethylene, or xelon to maintain signal quality

Coaxial Cable and Connectors for Ethernet Networks

  • Connector N male-to RG213 cable
  • Connector PL: RG58 cable
  • Connector PL: RG213 cable
  • Connector N male-to RG212 cable
  • Connector F for RG59 cable
  • Terminator BNC: 50 ohm cable RG58

Advantages and Disadvantages of Coaxial Cable

Advantages:

  • Good combination of large bandwidth and excellent noise immunity
  • Can handle high traffic and speeds up to 100 Mbps
  • Can transmit over longer distances than STP and UTP
  • Cheaper than fiber optic cable
  • Well-established technology

Disadvantages:

  • Lacks flexibility
  • Relatively high price

Fiber Optic Cable Composition

  • Optical fibers are strands of extremely compact, high-purity glass
  • The thickness of a fiber optic cable is similar to that of a human hair
  • Made from high-temperature silicon

Refraction and Reflection

Refraction: The change in direction of a wave as it passes from one medium to another, e.g., a spoon appearing bent in a glass of water.

Reflection: When light passing from one medium to another changes its speed, causing some of the light to bounce off the interface between the media, e.g., light reflecting off a glass surface.

Fiber Types and Their Differences

Multimode Fiber: Allows light beams to travel through multiple paths or modes. It is used for distances under 1 km, is simple to design, and has a lower cost. However, it has a lower bandwidth and a maximum distance of 2 km.

Singlemode Fiber: Only allows a single light beam to propagate. It has a smaller core size (8.3 to 10 microns), greater bandwidth, and a maximum distance of 100 km.

Advantages of Fiber Optic Cable

  • Safer due to no light loss during transmission
  • Reduced dimensions and weight
  • Immune to noise and interference
  • Real-time image and sound transmission
  • Unlimited bandwidth potential

Types of Fiber Connectors

ST (Straight Tip): Similar to the SC connector but requires a rotation for insertion, similar to coaxial connectors.

SC (Subscriber Connector): A direct insertion connector commonly used in Gigabit Ethernet switches.

Fiber Jumper Cables

Fiber jumper cables are essential for ensuring the performance of a fiber optic network. Their quality should be analyzed in three parts: the connector, the cable, and the manufacturing process.

Types of Multimode Fiber

  • Step-Index
  • Graded-Index

Maximum Distance of Fiber Optic Cable

  • Multimode: 2 km
  • Singlemode: 100 km