Understanding Ethernet - Cabling by Steve Roberts - Director of Technology, KE2 Therm Solutions, Inc

TM thermsolutions W.5.3 January 2011 Understanding Ethernet - Cabling by Steve Roberts - Director of Technology, KE2 Therm Solutions, Inc.

Network Media - Cable UTP cable follows precise specifications governing the number The network media is part of the physical layer of a LAN network of twists permitted per meter of cable. The Electronic Industry as defined by the OSI Open Systems Protocol Reference Model, Association/Telecommunications Industry Association (EIA/TIA) see Table 1. It is the medium through which the information is has established ratings of UTP cable shown in Table 2. passed from one device in the network to another. Although wireless methods of relaying information are becoming more Table 2 - Categories of Unshielded Twisted Pair and more prevalent, typically networks are connected using Category Speed Use cables. 1 1 Mbps Voice Only (telephone wire) Table 1 - OSI Reference Model 2 4 Mbps LocalTalk & Telephone OSI Layer Name Common Protocols 3 16 Mbps 10BaseT Ethernet 7 Application 4 20 Mbps Token Ring 6 Presentation HTTP FTP SMTP DNS 100 Mbps (2 pair) 100 BaseT Ethernet 5 5 Session 1,000 Mbps (4 pair) Gigabit Ethernet 4 Transport TCP SPX 5e 1,000 Mbps Gigabit Ethernet 3 Network IP IPX 6 10,000 Mbps Gigabit Ethernet 2 Data Link Ethernet 1 Physical When used for networking, UTP has four pair of 22 or 24-gauge copper wire, and has an impedance of 100 ohms. Twisted pair Multiple types of cables exist, and LANs can use a single type of for other uses, such as telephone wiring has an impedance of cable or a variety. The cable used is determined by the network’s 600 ohms. The standard connector for UTP is the RJ-45 connec- topology, protocol and size. Knowledge of the characteristics of tor. The RJ-45 is plastic and looks like a large telephone-style the different cables and how they relate to the network provides connector. In fact, RJ stands for Registered Jack which alludes to an essential part of developing a sound network. its origin in the telephone industry, see Figure 2.

Twisted Pair Cable Figure 2 - RJ-45 Connector Twisted pair cable is used in most telephone communications and in most Ethernet networks. There are two types of twisted pair cable, shielded and unshielded. Unshielded Twisted Pair (UTP) UTP cable has eight individual copper wires each covered by an insulating media. The wires are then twisted in pairs. The wires are twisted to eliminate “noise” generated by adjacent pairs and other electronics. The number of twists in each wire pair is varied to further eliminate noise. See Figure 1.

Figure 1 - Unshielded Twisted Pair Among the advantages of UTP cable for networking are the Varied number of twists in the wire pairs relatively small diameter, its ease of installation, flexibility with a variety of network architectures, and minimal cost. The dis- eliminates electronic interference from advantages are its susceptibility to electrical noise compared other wire pairs. to other networking media, and the shorter distance between signal boosts. Shielded Twisted Pair (STP) The susceptibility of UTP to electrical noise has made STP cable popular in environments where there is a lot of potential interference. Like the UTP cable the wires are twisted into four pairs with varying number of twists. Then each pair is individu- ally shielded with foil. The four pairs of wires are then wrapped in a group with metallic braid or foil. See Figure 3. STP cable is

TM Understanding Ethernet - Cabling thermsolutions generally installed with an STP data connector, however it can layer of Teflon or PVC is used. Fiber optic cable eliminates prob- be installed like UTP using an RJ-45 connector. lems with interference because it transmits light rather than electrical signals. Fiber optic is able to transmit over longer While STP is better at preventing interference than UTP, the distances than either twisted pair or coaxial and is capable of costs are higher and it is more difficult to install. Additionally, greater speeds. The cost to install, and the connectors for coaxial the metallic shielding must be grounded properly on both ends, are more expensive than twisted pair and coaxial. or it will act like an antenna and pick up unwanted signals. STP is rarely used in Ethernet networks. Ethernet Cable Summary

Figure 3 - Shielded Twisted Pair Specification Cable Type Metallic shielding prevents interference 10BaseT Unshielded Twisted Pair better, however it requires grounding on 10Base2 Thin Coaxial both ends to be effective. 10Base5 Thick Coaxial Thick Coaxial 100BaseT Unshielded Twisted Pair 100BaseFX, BX, SX Fiber Optic 1000BaseT Unshielded Twisted Pair Unshielded Twisted Pair 1000BaseFX, BX, SX Fiber Optic Coaxial Cable Coaxial cable has a single copper conductor in the center, sur- rounded by a layer of flexible insulation, which is then covered by a layer of woven copper braid or metallic foil. The foil layer Cable is the medium through which information moves from provides shielding from interference, as well as acting as the one device to the other. The type of cable chosen for a network second wire in the circuit. Covering the coaxial construction is a is related to its topology. Understanding the characteristics of cable jacket. Although coaxial cost more than UTP, it is still rela- different cable types is necessary for the development of a suc- tively inexpensive, and allows the cable to be run over longer cessful network. distances, this means it requires fewer boosts from repeaters. Disadvantages of coaxial include the thickness, which can reach 1 centimeter in diameter. Generally, as cable thickness increas- Additional Educational Materials es, so does the difficulty in working with it, and the expense Visit www.ke2therm.com to find articles on these topics: to install it. Another issue associated with coaxial is improper grounding during installation, resulting in electrical noise and W.1.1 Frost and Defrost: How it happens, why it is signal interference. There are two types of coaxial thicknet and needed. thinnet. W.9.1 Basic Thermodynamics for Refrigeration and Air Thicknet Conditioning Part 1 As the name implies thicknet has the larger diameter of the two. W.9.2 Basic Thermodynamics for Refrigeration and Air It features an extra protective plastic cover that helps keep mois- Conditioning Part 2 ture away from the center conductor. With its diameter reaching 1 cm, thicknet can be too rigid to install in some situations, and W.9.3 Basic Superheat, Saturation and Subcooling is generally used for special purpose installations or as the back- bone in a linear bus network. W.9.4 Electricity 101

Thinnet W.5.1 Understanding Ethernet Communications Thinnet, has an outside diameter of only .35 cm and was used - Networks in Ethernet networks. Its thinner diameter allowed it to be used W.5.2 Understanding Ethernet Communications where twists and turns were necessary. Despite its flexibility, the - Topologies issues arising from improper grounding of coaxial cable have basically eliminated thinnet from use in Ethernet networks. W.5.4 Understanding Ethernet Communications - Protocols Fiber Optic Cable Fiber optic cable is built around a center core made of glass or W.5.5 Understanding Ethernet Communications plastic fibers. A plastic coating cushions the fiber center and Kev- - Glossary lar fibers help strengthen the cables. Then an outer, insulating

Copyright 2011 KE2 Therm Solutions, Washington, Missouri 63090 KE2 Therm Solutions 209 Lange Dr. . Washington, MO 63090 1-888-337-3358 . www.ke2therm.com ® thermsolutions Q.5.5 April 2011 Making Ethernet Cable Quick Start Guide

Quick Start Step-by-Step directly connect one computer to another computer (or 1 Purchasing ready made Ethernet cables is often expen- device) without going through a router, switch or hub. sive, and can lead to wasted cable. Purchasing a bulk box of Category 5E (CAT-5E) cable, cutting it to the needed 3 Cut into the plastic jacket 1 inch from the end of the cut length, and attaching crimpable RJ-45 connectors to the cable using a cutting/stripping tool. (Available in Ethenet cut ends is much easier. Starter Kit p/n 20168.)

1 The items needed to make your own cable are shown in # 1. They include bulk cable, RJ-45 crimpable connectors 2 Straight Through sold in bulk, and an RJ-45 crimping tool. 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 2 There are two types of Ethernet cables you can assemble: Straight Through and Crossover. With clip pointed away from you Straight Through - It is recommended that you duplicate Pin 1 color order as shown in # 2. Note the green pair is not side Pin 8 by side like the other pairs. This configuration allows for longer wire runs. o O g B b G br BR o O g B b G br BR

Crossover Cables - The purpose of a Crossover cable is to

Bulk Ethernet cable - Cat-5 Crossover Cables

1 2 3 4 5 6 7 8 With clip pointed away from you Pin 1 Pin 8

o O g B b G br BR g G o B b O br BR Bulk RJ-45 crimpable connectors

RJ-45 crimping tool 3

1 inch

1/2 inch 1 inch

Q.5.5 April 2011 Page 2

Making Ethernet Cable ® thermsolutions Quick Start Guide

Un-twist and pair the similar color wires 4 6

5 Pinch the wires between thumb and fingers and straight- en the wires. Line the cables to form a straight through standard CAT 5E cable, see #2. 1/2 inch 6 Use scissors to make a straight cut across the wires, 1/2 inch from the cut sleeve to the end of the wires.

7 Push the wires into the connector. Note the position of the gray plastic shielding. The shielding must go inside the connector to be locked in place. Additionally, all of the wires must be all of the way in. There should be no short wires. 7

8 To crimp the cable, carefully place the connector into the crimper and cinch down on the handles tightly. The copper splicing tabs on the connector will pierce into each of the eight wires. There is also a locking tab that holds the gray plastic sleeve in place for a tight compression fit. When you remove the cable from the crimper the cable is ready to use. View from TOP

9 Repeat the steps for the other end of the cable. Wires must go all 1 inch the way in. There can be no short 4 wires.

Cable shielding must go into the connector.

5 8

1/2 inch