The Basics of Telecommunications pps

Chapter One - Telecommunication Basics...15 Introduction...15 Purpose ...15 Relationship to National Architecture ...16 Open System Interconnection Model OSI ...16 Telecommunication

Telecommunications Handbook for Transportation Professionals The Basics of Telecommunications

Final Report

September, 2004

Notice This document is disseminated under the sponsorship

of the Department of Transportation in the interest of

information exchange

The United States Government assumes no liability for its contents or use thereof

FHWA-HOP-04-034

5 Report Date

August, 2004

4 Title and Subtitle

Telecommunications Handbook for Transportation Professionals

The Basics of Telecommunications

6 Performing Organization Code

7 Author(s)

Sheldon Leader 8 Performing Organization Report No

10 Work Unit No (TRAIS)

9 Performing Organization Name and Address

11 Contract or Grant No

13 Type of Report and Period Covered

12 Sponsoring Agency Name and Address

14 Sponsoring Agency Code

Readers of this handbook should gain an understanding of the basic technologies underlying most telecommunications systems designed to transmit both voice and data information

17 Key Word

Telecommunications 18 Distribution Statement

19 Security Classif (of this report) 20 Security Classif (of this page) 21 No of Pages

287 22 Price

This Page Intentionally Blank

F OREWORD

This h and bo o k was creat ed t o p rovid e indi vidu als resp ons ible f o r man agin g and imp lementin g T raffi c Si gnal, and F reeway Managem en t p ro grams with an und ers tandin g of th e bas i c tech no lo gi es of t elecom mun icatio ns Th e h andb oo k p ro vides a

b ri ef lo o k at th e his to ry of telecom muni catio ns so that it s read ers m ay gai n an un derstan din g of w hy vario us p ro cess es exis t, and how t h e t echn ologi es ev olv ed Th e handb oo k is n o t desi gn ed to b e us ed as a specifi catio n fo r telecom mu nicati o n syst ems

Th e t ech no lo gi es asso ci at ed with t eleco mmu nicati ons are in a

co nst ant s tate of ch an ge This h and bo o k was w rit ten ov er a tw o yea r peri od b etw een Au gust , 2 00 2 and Jun e 20 04 D u ring t h i s time, a num ber of em ergi ng t ech no lo gi es began to reach m atu rity

Th e mos t si gni ficant of th es e, wi reless int ern et access , and voi c e over IP have caus ed th e maj o r carri ers (teleph on e comp anies) t o ann oun ce t h e co nst ru cti on o f n ew f acili ties t o p rovid e “Int ern et Teleph ony ” s ervi ces This co nst ru ctio n is t o st art in 2 00 4

We lco me t o t he futu re!

A CKNOWLEDGEMENTS

Th e aut ho r wou ld li ke t o acknowled ge t he i nv alu able co nt ribu tio n s

of th e fo llowin g i ndividu als fo r v olunt eerin g t h ei r tim e to revi ew this d o cum ent :

• Ka re n J eh ani an , KM J C onsu lt ing , Ha ve rf o rd , P A

• Ja mb a la ( J ay) R uit , Edw a rds and K el c ey , I n c , Wes t Ch est e r,

P A

• J eff e ry Pu rdy , Edw a rds and Ke l c ey, I nc , Wes t Ch est e r, P A

• Ric h a rd E asl ey , E2 E n gin e e ri ng , Ash bu rn , VA

• Ray Caud u ro , G DI Syst e ms, LLC , N ewp o rt, O R

Th e fo llowin g i ndividu als su ppo rted t h e o verall develop ment o f this d o cum ent :

• Pau l O ls on , F H WA, Sa n F ra n c isco , C A

• Bill Jo ne s, FH WA, Wa shi ngto n, D C

T ABLE OF C ONTENTS

1 Chapter One - Telecommunication Basics 15

Introduction 15

Purpose 15

Relationship to National Architecture 16

Open System Interconnection Model (OSI) 16

Telecommunications History 18

Handbook Organization 20

2 Chapter Two – Fundamentals of telecommunications 23

Introduction 23

Transmission Media 25

Media Consideration Factors 26

Wireline Media 28

Transmission Signaling Interfaces 52

Data & Voice Signaling - Basics 53

Electro-Mechanical Signal Interfaces 54

Video Transmission 55

Video Compression 57

Video CODECS 57

Video Compression 58

Streaming Video 60

Basic Telephone Service 61

Multiplexing 63

Time Division Multiplexing 64

Packet Division Multiplexing 65

T-1 Communication Systems 66

Transporting Digital Communications via an Analog Network 68

High Capacity Broadband Transmission 69

T-1/DS-1 & T-3/DS-3 70

DSL 71

SONET 72

ATM 73

FDM 75

WDM – CWDM & DWDM 75

Ethernet 76

Conclusions 81

3 Chapter Three – Telecommunications & The National ITS Architecture 83

Introduction 83

Overview – The National ITS Architecture 84

Vehicle-to-Vehicle (VtV) 85

National ITS Architecture Flows & Telecommunications 89

Market Packages 90

Example Illustration 92

Architecture Flows 97

Rural Systems 98

National Transportation Communication for Intelligent Transportation Systems Protocol (NTCIP) 100

Conclusion 105

4 Chapter Four – Developing the Telecommunication System 106

Introduction 106

Selecting the Consultant 106

There’s no substitute for experience 107

Different Telecommunication Design Specialties 108

Types of Telecommunications Experience 108

Knowledge of Telecommunications Systems Relationships 109

Educational Qualifications 110

Requirements Analysis 113

The “Gee-Whiz” Factor 115

Keep expectations realistic – ask questions 115

A Systematic Engineering Approach to the Requirements Analysis 116

Key points to consider: 117

Ask The Questions 117

Creating The Requirements Document 121

Three Basic Systems Types: 122

Developing a Budget 122

Conclusion 123

A few simple guidelines to follow: 123

5 Chapter Five – Telecommunications for Field Devices 124

Basic Communication Circuits for Field Devices 126

Basic Circuit Types 126

The Design Process 128

Traffic Control Device Circuits 134

Traffic Control System 135

Basic Data Circuit Types 136

Basic Traffic Device Type Communication Circuits 138

Basic Video Communication Circuits 141

Video-over-IP (VIP) 147

Basic Traffic and Freeway Management Networks 151

Basic Device Networks 151

Complex Communication Networks 152

Summary 160

Network Topology 162

Point-To-Point Networks 163

Star Networks 163

Ring Networks 164

Mesh Networks 165

Network Redundancy 167

Conclusion 167

Why create a Maintenance Budget? 169

Creating the Maintenance Budget 172

Warranties, Extended Warranties & Service Plans 177

Warranties 178

Extended Warranties 179

Relationship of Warranties to System Specifications 181

Service Plans 181

Conclusions 184

7 Chapter Seven – System Examples 185

Introduction 185

Utah DOT System 186

Background 186

The System - Existing 188

The System - New 191

City of Irving Texas 193

Background 193

Proposed Update 194

5.8 GHz Attributes 196

Theory of Operation 197

The Irving Proposal 198

Tie-in To Main Communication Network 202

Conclusion 203

8 Chapter Eight – Construction 204

Introduction 204

Handling and Installation of Fiber Optic (and Copper) Communications Cable 205

Receiving and inspecting fiber optic cable 206

Unloading, moving and storing cable 207

Testing the cables 208

Documentation and record maintenance 210

General Cable, Installation and Design Guidelines 211

Cable Pull-box/Splice-box Placement 211

Cable Installation and Pulling Guidelines 212

General Cable Construction Guidelines 214

Aerial Construction 215

Direct Burial Construction 218

Conduit Construction 219

Wireless Systems Construction 220

Planning for Wireless Systems 221

A Word About Antennas 224

Guidelines for Handling & Installation of Wireless Antenna and Transmission Cable 224

Conclusion 226

Resources: 226

9 Chapter Nine – The internet 227

Introduction 227

What is the Internet? 227

How Does the Internet Work? 233

Addressing – Formats 235

Types of Internet Networks 237

Role of the Internet for Traffic, ITS, Freeway Management & Traveler Information 239

Use of the Internet for Center-to-Center Communications 241

Conclusions 246

10 Chapter Ten – The Future 247

Introduction 247

Circuit Switched Vs Packet Switched 247

Trends for Transportation 249

High Speed Ethernet 249

Resilient Packet Ring (RPR) 251

Broadband Wireless 252

Radio Frequency Identification (RFID) 253

Conclusions 254

11 Appendix 256

IEEE 802 Standards & Working Groups 256

Comparison Analog Voice & VoIP 257

Calculating Fiber Optic Loss Budget 258

Criteria & Calculation Factors 258

Calculating a “Loss Budget” 259

Rural Telecommunications Requirements Testimony 262

Steve Albert – Senate hearing 262

About the Author 268

Glossary 269

L IST OF T ABLES

Table 1-1: OSI Protocol Stack 17

Table 2-1: Twisted-Pair Communication Cable Category Ratings 31

Table 2-2: Fiber Optic Cable Classifications 35

Table 2-3: Fiber Cable Color Identification Chart 36

Table 2-4: Fiber Optic Cable Buffer Types 39

Table 2-5: Comparison Single Mode Fiber & Multimode Fiber 43

Table 2-6: Frequencies for Unlicensed Radio Systems 49

Table 2-7: CEA Estimates of the Number of Low Power Radio Devices 50

Table 2-8: Comparison of TDM & PDM 66

Table 3-1: DSRC Vehicle-Roadside Relationships 87

Table 3-2: Communication Needs & Requirements 94

Table 3-3: NTCIP Device Management Protocol List 104

Table 3-4: NTCIP List of Systems Management Protocols 104

Table 5-1: Location of Field Controllers 129

Table 5-2: Location & Data Requirements Table 131

Table 5-3: DB-25 Connector Cable 133

Table 5-4: Voice, Video & Text Transmission Requirements 143

Table 5-5: Field Device Location 158

Table 6-1: Example Communication Device Inventory List 171

Table 6-2: Technician Experience Classification 173

Table 7-1: Deployment Cost Estimates 191

Table 8-1: Example of Manufacturer Recommended Span Lengths for Areial Cable Segments 216

Table 9-1: Internet Communication Elements 242

Table 10-1: Comparison Traditional CCTV vs VIP Systems Requirements 250

Table 11-1: IEEE 802 Standards List 256

Table 11-2: Fiber Loss Budget Calculation 259

L IST OF F IGURES

Figure 1-1: Diagram - NTCIP Standards Framework 17

Figure 1-2: Telecommunication Timeline 20

Figure 2-1: RJ45 Connector 29

Figure 2-2: Twisted Pair Cable 30

Figure 2-3: Co-Axial Cable Illustration 32

Figure 2-4: Basic Fiber Optic Strand Construction 33

Figure 2-5: Fiber Optic Cable Illustration 36

Figure 2-6: Diagram of Basic Connector Wiring 54

Figure 2-7: Illustration of Basic Telephone Call Process 62

Figure 2-8: TDM Process Flow Chart 64

Figure 2-9: Flow Chart - PDM Process 65

Figure 2-10: Diagram of Computer Digital Output Converted to Analog using a MODEM 67

Figure 2-11: Diagram of Analog Inputs to T-1 Mux 69

Figure 2-13: DWDM Channels 75

Figure 2-14: Diagram - Typical Office LAN 80

Figure 2-15: Diagram - Metro Area Network (MAN) 81

Figure 3-1: National ITS Architecture Communications Sausage Diagram 83

Figure 3-2: Diagram - Mobile 2-Way Radio Network 86

Figure 3-3: National Architecture EM-4 Market Package 90

Figure 3-4: EM-4 Market Package with Telecommunications Flows 92

Figure 3-5: EM-4 Market Package with "Sausage Diagram" Elements 93

Figure 3-6: TMC Area of Responsibility 94

Figure 3-7: Diagram - TMC to EMA Link 95

Figure 3-8: Diagram - TMC to EMA with Fiber Communication Link 96

Figure 3-9: Diagram - TMC to EMA Comm Link Rural Setting 97

Figure 3-10: Diagram - TMC to EMA Rural using Leased Telephone Lines 98

Figure 3-11: NTCIP Standards Framework 100

Figure 4-1: Field Devices Communication Link Requirements 113

Figure 4-2: Chart Relationship Communication to Overall System 114

Figure 5-1: Diagram - Technology Flow 124

Figure 5-2: Diagram - 3 Types of Communication Circuits 127

Figure 5-3: Napkin Sketch of Communication System 129

Figure 5-4: Location Map 130

Figure 5-5: System Schematic 132

Figure 5-6: DB-25 Connector 134

Figure 5-7: DB-9 Connector 134

Figure 5-8: Modem Block Diagram 136

Figure 5-9: CCTV Circuit Diagram 137

Figure 5-11: Diagram Field Controller to Host Computer 138

Figure 5-12: Diagram - Point-to-Multipoint 139

Figure 5-13: Diagram - Multidrop System 140

Figure 5-14: Diagram - FDM Hub Circuit 144

Figure 5-15: Diagram - CCTV with CODEC 145

Figure 5-16: Diagram - Typical CODEC Communication Circuit - 1990's Deployment 147

Figure 5-17: VIP Basic Camera System 149

Figure 5-18: Diagram - Add-on Conversion to VIP 150

Figure 5-19: Diagram - Basic Traffic Device Communication Circuit 151

Figure 5-20: Diagram of described system 153

Figure 5-21: Diagram STSS Communication System 154

Figure 5-24: Diagram - Site Equipment 159

Figure 5-25: System Block Diagram 160

Figure 5-26: Diagram - Point-to-Point Network 163

Figure 5-27: Diagram - Star Network 164

Figure 5-28: Diagram - Ring Network 164

Figure 5-29: Diagram - Mesh Network 166

Figure 6-1: Photograph of a Fiber Optic Modem 170

Figure 7-1: Diagram UDOT Current System 190

Figure 7-2: Graph - Comparison of Savings Realized by UDOT Converting to an IP Architecture 191

Figure 7-3: Diagram - Comparison Multi-Drop VS Ethernet 192

Figure 7-4: Diagram - Wireless Channel Alignment for 360 Degree Coverage 195

Figure 7-5: Diagram - Channel Re-use Plan for Wide Area Coverage 197

Figure 7-6: Diagram - Proposed Channel Re-use Plan 198

Figure 7-7: Drawing - Typical CCTV Site 199

Figure 7-8: Typical CCTV Site Schematic 200

Figure 7-9: Map of Proposed Irving Texas System 201

Figure 7-10: Schematic - Microwave Backbone Configuration 202

Figure 7-11: Diagram - Microwave Backbone 203

Figure 8-1: Fiber Cable Route Construction – Photograph Courtesy Adesta, LLC 204

Figure 8-2: Fiber Cable Route Construction – Photograph Courtesy Adesta, LLC 204

Figure 8-3: Fusion Splicing Fiber Strands - Photograph Courtesy Adesta, LLC 209

Figure 8-4: Aerial Fiber Optic Cable Splice Box - Photograph Courtesy Adesta, LLC 212

Figure 8-5: Typical Telephone Pole 217

Figure 8-6: Installation of Wireless System - Photograph Courtesy GDI Systems, LLC 220

Figure 8-7: Example of Antenna Coverage Pattern - Antenna Specialists Products 224

Figure 9-1: Actual Sketch of the Original Internet Concept 228

Figure 9-2: Map - Location of Major MCI Internet Nodes in United States 229

Figure 9-3: Diagram General Internet Architecture 232

Figure 9-4: Diagram - Traveler Information Provided via the Internet 234

Figure 9-5: National ITS Architecture Sausage Diagram with Internet added 240

Figure 9-6: Internet Elements Schematic 243

Figure 9-7: Schematic - Multiple Agency Center-to-Center Links via the Internet 244

Figure 9-8:ITS Center-to-Center Communication Diagram 245

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1 C HAPTER O NE - T ELECOMMUNICATION

Introduction

Th e “Telecommuni cati ons Hand book for Tran s portation

P rof essi on als ” was o ri gi n ally pub lis hed in 198 7 as th e

“Co mmuni cati ons Hand bo o k fo r Traf fi c Co nt ro l Sy st ems” Th e

fi rs t ( and on ly) upd at e was initiated in 19 91 , and pu blish ed i n

199 3 Giv en th e signifi can t ad vances in th e t echn o lo gy o f telecomm uni catio ns, and t h e co mplexi ties of Traffic and ITS syst ems d eploym ent its is n ecess ary to creat e a n ew ( rat her t han

a revisio n) h and bo o k p ro vidin g a b ro ad er v iew o f telecomm uni catio ns t echn ology as appli ed f o r t raf fic an d

t ransp o rt atio n pu rp os es Thi s h and bo o k p rovid es a b ro ad ove rvi e w

of t elecomm uni catio ns t ech n ology and hi sto ry

Purpose

Th e “Telecommuni cati ons Hand book for Tran s portation

P rof essi on als ” is int en ded to p ro vid e an in t rodu ction t o telecomm uni catio n techn olo gy and p ro cess f o r t rans po rtatio n

en gin eers and p ro ject man agers i nvo lv ed in th e d es ign an d dep loy ment of t raffi c si gn al and freeway m an agement syst ems

Th e handb oo k can b e us ed as a res ou rce th at p rovid es an overvi ew

of t h e v arious t echni cal is sues as so ciat ed wit h t he plannin g , desi gn , op erati on , and m an agem en t o f a co mmuni cati ons s ystem It

is inten ded to p rovid e th e user with a b ett er un ders tandin g o f appli ed comm uni cation s t ech nolo gy and th e co nsid eratio n s fo r u s e

in f reew ay and su rf ace s t reet n etworks

Th e int en ded audi en ce is t ranspo rt ati on p rof es sio nals wh o may b e invo lv ed with , o r respon sib le fo r any p h as e in t h e li f e cy cle of a

t raf fic signal or f reew ay man agem ent cont ro l n etw ork Thi s includ es all pu b lic o r p riv at e “p ractiti on ers ” ( e.g., m an agers , supervis o rs , en gin eers , p lann ers , o r t echni ci ans) inv olved with an y issue o r d eci sion ( e.g., p o licy, p ro gram , fundi ng, o r syst em implem en tati on) and w ho may di rect ly o r indi rect ly in f lu ence th e perf orman ce of t raffi c on lo cal art eries or f reew ay f aci liti es

Th es e activiti es m ay in clud e, bu t no t b e li mit ed to , p lan ning an d desi gn , op eratio nal st rat egi es , p rograms , and s ervi ces th at suppo rt contin uous m an agem ent o f t rav el an d co nt ro l o f t raf fi c, and th e t ech no lo gy i nf rast ru ctu re t o p rovid e th es e cap ab iliti es

Telecom muni catio ns sy st em s as p art o f th e N ati o nal ITS Arch it ectu re are th e con necting p at hways t h at bin d th e vari ou s elements of t raf fic si gn al, f reew ay m an agement, an d

t ransp o rt atio n sys t ems to geth er Th e Nati on al ITS Arc hit ectu re

“s aus age diagram ” indi cat es how t hese elem en ts are bou nd

to geth er, bu t do es no t sp eci fy t he t eleco mmu nicati on s ys tem Th e dev elop ers of t he N ati on al ITS Archi tectu re und erst ood th at each t elecom muni catio n sys tem wou ld b e uniq uely desi gn ed t o meet th e n eeds of each p ro j ect

Th e signifi cant div ersity o f co mmu nicati ons t ech no lo gi es and th e overall comp lexity of t raffic si gnal, freew ay managem ent , and

t ransp o rt atio n syst em s hav e creat ed a n eed f o r t ra ffi c an d

t ransp o rt atio n p ro fessio nals t o imp lem ent th e Syst em s Engi neeri ng P rocess (S EP) This hand book p rovi des a summ ary (Chap ter 4) of how t o apply an SEP to th e d ev elopm ent o f a telecomm uni catio ns syst em , fo r t raf fi c signal and f reeway man agem ent syst em s d ev elop ment

Open System Interconnection Model (OSI)

Th e OS I mod el is an Int ern ation al St an dards Organi zati o n (ISO) stan dard th at d efin es a f ram ew o rk fo r im plem enti n g telecomm uni catio n and s oft ware p rotocols The OS I mod el i s

o rgani zed in to s ev en hi era rchal lay ers Co nt ro l is pas sed f rom o n e lay er to th e n ext st artin g at th e app licati on lay er and p roceedin g down to each su cces siv e layer and back as requi red fo r any giv en

p ro cess Most of t h e fu nctio nality of t h e OSI mod el exis ts in al l

co mmu nicati ons syst ems - h owev er, tw o o r t h ree lay ers may b e

co mbin ed int o o n e Th e m ost signifi cant ro le of th e OS I mod el i s

to s erv e as a ref erence fo r th e d ev elopm en t o f o th er p ro to co l stacks A d et ailed exp lanati on of th e OSI M od el is p ro vided i n

th e Add en dum s ectio n of t hi s han db oo k Tab le 1-1 , p rovid es a lis t

of t h e OSI Mod el P ro t ocol S tack

th e types of d evi ces th at exis t at th e ph ysi cal and d at a li n k lay ers of t h e p rot o co l st a c k All m edi a and m ost of th e p ro to co l

co nv ert ers are con sid ered as lay er on e it ems So m e

co mmu nicati on hardware d evices are d esign ed to op erat e at higher lay ers A n etw ork rou ter is oft en referred t o as a “lay er 3

rou t er” This is o ne o f th e few ex amp les of com m unicati o n

hardw are th at is d esign ed to fu n ctio n ab ove lay er tw o M os t

co mmu nicati on sy st ems are not d esi gn ed usin g t h e OSI p ro to co l stack This is b ecaus e t he h ardware v end o rs h av e alread y taken

th e OSI m od el into consi deratio n fo r t h e design o f th ei r

p rod ucts T h e RS 23 2 a nd R J4 5 c onn ect o rs bui lt int o t he 20 7 0

t raf fic cont ro ller are already layer on e comp li ant S erving as a

p rotocol st ack mod el, OS I is used as th e reference fo r the dev elopm ent of mos t other co mmuni cati ons p rotocols Th e Nati on a l T ra nsp o rtatio n Co n t rol In terf a c e P ro to co l ( NT CIP)1 has

a sp ecially d ev eloped p rot o co l st ack b as ed on th e OS I m o del

Noti ce (fi gu re 1-1) t hat th e NTCIP p roto col st ack is mo deled o n

th e OSI s tack, and has em bed ded t eleco mmuni cati on s tand ards Commu ni cati on syst em d esi gn ers wo uld simp ly u se t he p re-defi n ed telecomm uni catio n st and ards How ev er, d ev elop ers o f s oftw are

co nt ro l sys tems mu st b e acutely aware o f t he N TCIP p ro to co l stack N TCIP and its ro le i n th e d ev elopm en t o f a com m unicati on syst em is exp lain ed in Ch apt er 3

Telecommunications History

Th e hist ory of m od ern-d ay commu nicati ons t echn ology can b e s ai d

to hav e st arted wh en S amuel Mo rs e i nv ent ed th e wi reli n e telegraph in 1 832 How ev er, it w as Alex ander Graham Bell’s inventio n o f t he teleph on e, i n 187 4 , t hat led t o t he developm en t

of ou r p res ent d ay commu ni catio ns t echno logy Mo rs e h ad si mply creat ed a way f o r hum an s to ext end t h ei r abi lity t o t rans f e r info rm ati on – inst antly – ov er great dist ances Bell gav e us t h e abi lity to h av e t h e m ost in timate f o rm of comm uni cati on ov er distances – t h e us e o f ou r vo ices

Th e co n cep t o f t h e t elep ho ne i nst rum ent – and t h e sys tem th at

F i g u r e 1 - 1 : D i a g r a m - N T C I P S t a n d a r d s F r a m e w o r k

ef fici ent voi ce comm uni catio n netw o rk It was n’t unti l 2 00 4 th at maj o r t elecommu ni cati on carri ers ann oun ced t h e n eed to dev elop , and supp o rt , a n etw o rk design ed f o r th e pu rpos e o f t ra nspo rti n g digit al data

Th e wi reless t elegrap h ( now ref erred to as radi o) w as in v ent ed b y Guillermo M arconi in 1 89 62 Wh en wi reles s com muni cat ion was finally able t o b e used fo r voice t ransmis sion , it emu lat ed th e telep h on e sys tem

F rom 1 87 4 to 1 98 0 , c om mu nicati on n etw o rks a rou nd t he w o rld were co nst ru ct ed t o f aci li tat e t he ef fi cient and econo mica l

t rans missio n of voi ce co nv ersatio ns Mu ltip lexin g and digi ta l

t rans missio n s yst ems were dev elop ed to “cram ” m o re v oic e

co nv ersation s into th e ex istin g copper wi re commu nicati o n facili ti es

Th e Int ern et , fi rst d ev elop ed in 1 97 3 as a p roj ect f o r th e U.S Dep artm ent of D ef ens e Advan ced R es earch P ro ject s Agen cy ( ARP A) , i niti at ed a p ro f ound chan ge in th e fut u re d ev elo pment o f

co mmu nicati ons n etw o rks an d tech no lo gi es Ori gin ally called th e Arp anet – lin ki ng s ev eral Uni versiti es and res earch labo rato ri es –

it evo lv ed i nt o t h e w o rld wide w eb ( WWW) Du rin g t his peri od ,

th ere w ere a num ber of s igni fican t t echn olo gy adv an ces an d gov ern ment enf o rced corporat e reorg a ni zations th at h e lpe d t o

ch an ge t h e di rection of com muni cation s syst ems d ev elop ment:

1 Computi ng and com muni catio n s tech no lo gi es were p ro vid ed a big bo ost by t h e inv en tion o f th e in t egrat ed ci rcuit ( IC) in

195 9 Th e IC permi tt ed developm ent and manuf actu re o f smaller and m o re aut om at ed co mmu nicati on d evi ces at a v ery low co st

2 Th e Cart erp ho ne D ecisio n, by th e U.S S up reme C ou rt , in

196 8, m ade it p ossib le fo r t he con necti on of no n-t elep h on e

co mpany ow n ed d evi ces (un ti l t his poi nt , o nly d evi ces ow ned and op erat ed by t h e t elep ho n e co mpanies were p ermitt ed)

3 In th e 19 70s , fib er st rands were fi rst us ed as a

co mmu nicati on m edi um

4 In 19 83 , t h e U.S S up reme Cou rt m and at ed reo rgani zati o n

of AT& T w as enf o rced

2 Historically, Marconi is credited with the invention of the wireless telegraph, however, a landmark June 21, 1943 supreme court decision stated

dem and fo r co mput er and d at a comm uni catio n servi ces fo rced a

ch an ge i n t h e natu re o f th e d ev elopm ent of com mu nicati on s netw o rks By 199 5 , mos t ins tallati on o f co mmu nicati ons netw o rk s was d ev ot ed t o t he effi ci en t t ransmissi on of data gen erat ed b y

co mput ers Howev er, t h es e netw o rks w ere s till b as ed o n a voi c e

co mmu nicati on d esi gn

Th e d ev elopm ent and i nt rodu cti on o f b ro ad ban d dat a

co mmu nicati ons st an dards ( IEEE 8 02 S eri es3) helped to create a dem and fo r comm uni cation s netw o rks d esign ed to supp o rt dat a

co mmu nicati ons

By 2003, wi reles s (cellu lar t elep hone) networks w ere av ailable t o almos t every lo cati on of t h e Unit ed St at es ( remo t e wild ern es s areas sti ll lack cov erage) Acco rdi ng t o th e Cellula r Telecom muni catio ns & Int ernet Asso ci ati on (CTIA), t h ere w ere

mo re t han 148 mi lli on wi reless su bs cri b ers, and 9 2% w ere usi n g digit al servi ce

A tim eli ne of t h e suppo rt fo r t raditi on al v oi ce t ran smissio n servi ces versu s dat a t ran smissio n servi ces mi gh t appear as

fo llows:

By 20 03 , 6 3% o f Am eri cans us e t h e in t ern et , and 31 % of ho m e users h av e b ro adb an d access4 In early 2 00 4, Veri zon , an noun ced

a m aj o r up g rad e of i ts b asi c t el ep ho n e n etwo rk t o suppo rt

“Int ernet Telep hony ” or Vo ice over Intern et P rotocol (VoIP)5 Sout hern Bell C o rporatio n ( SBC) als o ann oun ced similar upgrade s

fo r its n etwo rks

Handbook Organization

Th e Teleco mmuni cati ons Hand book fo r Tran sportatio n

P rof essi on als is o rgani zed t o p ro vide t h e reader wit h a lo gi cal flow of i nf o rmatio n with a des criptio n o f v ari ous co mm unicati o n

Data Network Dominance Starts

F i g u r e 1 - 2 : Te l e c o m m u n i c a t i o n Ti m e l i n e

fo r th e d ep loy m ent of F ree way Man agem ent and Traffi c Si gn al syst ems Techni cal d es cri ptions are kept at a minimu m

en gin eerin g lev el to p ro vide non- commu ni cati on p ro f essi o nals wit h

a b asi c un ders tandin g of t h e tech no lo gi es

Chap ter Two – Teleco mmuni catio ns Fun dament als C om m unicati on tech no lo gy i s p rovid ed i n a “basi c to co mplex” o rd er Th e ch apt e r starts wit h copper b as ed t ra nsmissi on m edi a and s tep s th e read er

th rou gh a p ro g ressio n o f t e rmino lo gy th at i n clud es : fi b e r opti cs ,

wi reless , vid eo mu ltip lexing and Et hern et sys t ems

Chap ter Th ree – Telecom muni catio ns & Th e N atio nal Archi tectu re

Th e chap ter i s a gen eral loo k at t h e relatio n ship o f telecomm uni catio ns s yst em s d esi gn an d t h e Natio nal IT S Arch it ectu re and NTC IP Th e read er wi ll b e m ad e aware of t h e fact th at N TCIP is not a st and ard , bu t a p ro to co l th at defin es

th e relati ons hip of t he many cu rrent ( and d evelopin g)

co mmu nicati ons st and ards f o r us e in a t raffi c signal, f reew ay man agem ent , o r t ranspo rt ation sy st em

Chap ter F ou r – D ev elopin g th e Teleco mmu nicati on S yst em Thi s

ch apt er p rovides t he read er with a syst em en gin eeri ng app roac h

to th e d esign of a co mmu nicatio ns syst em th at suppo rt s t raffi c and t ransp o rtation requi rem ents Th e chapt er p rovid es a step- by-step p ro ces s t hat sh ou ld resu lt in a co mmu nicati o n syst em requi rem ent s an alysis and p reli min ary design Th e p rim ary axio m that d rives th e d esi gn of a commu nicati ons s yst em is - “t here are

no abs o lut es! ” Fo r mos t com muni cation syst ems t h ere are us uall y sev eral w ays t o achi ev e th e d esi red res ult s A qualifi ed

co mmu nicati ons s yst em d esi gn er will gen erally p res en t sev era l diff erent app roach es and as k t he p roj ect manager t o make a decisio n

Chap ter Fiv e - Comm uni cati ons f o r Fi eld Devi ces Th e ch apt er

p ro vides an in-d ep th loo k at basi c sys tem confi gu rati ons fo r fi eld devi ces us ed in t raf fic si gn al and f reew ay m an agement syst em s Each fi eld d evi ce h as a speci fic s et o f co mmu nicati on s requi rem ent s

Chap ter Six – C omm uni cation Syst em M ain tenan ce M ain tenan ce o f

a telecom muni catio n syst em is essenti al Op erat o rs o f th es e syst ems must p rovid e fo r t h e care and f eedin g of t h e n etwo rk s that con nect all field d ev ices and op erational cent ers Th e

ch apt er dis cus ses t he n eed to creat e a bu dget fo r mai n ten an ce,

th e relation ship o f m anu fact u rer w arran t ees to m aint enance, an d

at “real-wo rld ” s yst ems dep loy ed by d ep artm ent s o f

t ransp o rt atio n Two sys tems are des cri bed to sh ow how simila r

p roblems us e di ff erent app roaches t o a so luti on

Chap ter Eight – Ins tallati on and Testi ng A majo r cost elem en t i n

th e dep loy m ent o f a com muni cation s syst em is ins tallati o n (co nst ru cti on) Very of ten , p ro je ct m an a gers as sum e t h a t p rop e r installation p ro ced u res are bei ng u sed by co nt racto rs Thi s

ch apt er p ro vid es guid elin es fo r p ro per h and lin g and in s tallati on

of com muni catio ns m edi a Wi relin e and wi reless m edi a are discus sed

Chap ter Nin e - The Int ern et Fi rst co nceiv ed and imp lem ent ed nearly thi rt y y ears ago, has had a p rofound effect on th e way individu als , p riv at e comp ani es and pub li c o rgan izati on s

co mmu nicat e o n a d ay-to -day basis Th e ch apt er i n this d ocu m en t will p ro vid e t h e read er w ith a basi c und erst andi n g of th e

co mposi tion of t h e In tern et, the Wo rld Wid e Web (WWW), how i t

wo rks, and h ow it can be us ed as p art of an ov erall

co mmu nicati ons and op eratio nal st rat egy f o r Traffi c Si gnal, F MS , and ITS sy st ems

Chap ter Ten - Th e Fu tu re An at tempt t o p rovid e s om e in sight o n

th e gen eral futu re of com m unicati ons syst ems and t he possib le impli cation s f o r t h e d ep loy m ent o f t elecom muni catio ns sy stems t o suppo rt F reeway Man agem ent and Traffi c Signal sy st ems

App endix A – C ont ains additi on al in fo rm ati on t h at read ers of t hi s handb oo k can us e f o r i nv est igatio n of additi on al reso u rces Th e

fo llowin g it ems are in clud ed i n this app en dix:

• List of I EEE 80 2 st an da rds a nd wo rkin g g ro ups

• Comp ari son of analog v oi ce and voi c e-over- IP ( VoIP)

• How to c al cu la te a fib e r op ti c l oss bud g et

• A dis cussi on of ru ra l t el e co m muni ca tion s req ui re me nts

Gloss ary – D efi nitio ns – will p rovid e a listin g of all t ermino lo gy used i n t his h an db oo k

ai r is t he t rans missio n medi um ov er whi ch soun d t rav els betw een mout h and ear Th e t rans mit ter and recei ver elem ent s o f a dat a mod em (su ch as th e typ e used in a t raffi c signal system

co nt ro ller b ox) may no t b e readi ly visi ble However, loo k at a schematic of its comp on en ts , and you will s ee elements labeled as

“XMTR” and “RC VR” The m od em’s t rans mission medi um i s typically copp er wi re, fib er, o r radio

Almos t all co mmuni cati ons n etwo rks h av e as t h ei r basis th e sa m e set of Telep hon y (Telep h o– N y) stand ard s and p racti ces “Ma Bell” (the Bell Teleph on e Sys tem and

Am erican Telephon e &

Telegrap h, an d ot h ers) sp ent

years and bi llions of do llars

creati ng, perf ectin g and

main tai nin g a

telecomm uni catio ns netw o rk

dedi cat ed t o p ro vidin g t he

most reli able v o ice

co mmu nicati on s ervi ce in t he

wo rld All ot h er commu nicat ion

tech no lo gy an d p ro cess evo lv ed b as ed o n t hat com mun icatio n s netw o rk E ngi neers and s ci en tists inv olv ed in t h e develop ment of new com muni catio n techn ologi es and p ro cess es h ad to mak e certai n t hat t hei r “p rod uct ” cou ld be us ed wit hin t h e exis tin g telep h on e n etwo rks An d, the t eleph on e comp any req ui red backw ard comp atibi lity Teleph on es m anu f actu red in 195 0 stil l

wo rk i n tod ay’s netwo rk Mo dems manuf actu red in 19 80 still wo rk

in th e cu rrent s yst em

As you read t h rou gh t his ch apt er, and th e rest of t he h and bo o k, pleas e keep in mind th at t elecom muni catio n st an dards , p ractices , and p ro to co ls w ere d ev el op ed fo r th e com muni catio n indu st ry Al l

Some communication transmission protocols were developed to work independently of the Telephone System

Ethernet, for example was created to facilitate data communication within a closed system that was contained within

an office building The Internet was created as a closed communication network

of th es e s yst ems mu st be adapt ed fo r us e in a t raffi c sign al o r

f reeway m an a gement s yst em

Tod ay , in No rt h Am eri ca, M exico, m ost o f Eu rop e and th e Pacifi c Rim , v oice s ervices are i n f act s en t as di git al si gn als an d

co nv ert ed t o an alo g jus t b ef o re leavin g ( an d arrivi ng at) th e servin g cent ral of fi ce, at th e en d-us er p oints Th e read er mi gh t

as k: “If voi ce is conv ert ed to digit al isn’ t th at th e sam e as dat a?” Th e answ er is no - “di gital t ransmis sion ” does n o t aut om ati cally inf er d at a commu nicati ons comp atibi lity An alo g

t rans missio n sy st ems can, an d do , carry d ata In telecomm uni catio ns, digi tal and an alo g are dis tin ct fo rms o f

co mmu nicati on t ransmissi on This ch apt er p ro vid es i nf o rmatio n

ab out th e b asi cs of t eleco m muni cation s - th e t ran smissi on medi a and t rans missio n syst em s, as well as an explan ati on of th e diff eren ces b etw een analo g and digit al t ransmis sion Tran smissio n medi a are t hos e elem ent s that p ro vide com muni catio n syst ems with a p ath on whi ch t o t ravel Transmi ssio n syst em s are th os e elements (hardware an d s of tware) t hat p rovid e m an agement of

th e commu ni cati on p ro cess and

th e us e o f t h e t ransmi ssio n p ath

Th e t eleco mmu nicati ons wo rld

would b e v ery simp le if the

distin ctio n b etw een t rans mi ssion

medi a and sys tems (p rot ocols)

were easily d efi n ed Oft en, a

specifi c t ransmi ssio n syst em will

only wo rk withi n a sp ecifi c

mediu m Sp read Sp ect rum Radi o

is on e example Radio (RF) i s th e

t rans missio n m edi um , and s p read

spect rum is th e t ransmissi o n sys tem (p ro to col) Alt ho u gh it i s possib le t o creat e a sp read spect rum commu ni cation s signal ov e r

wi relin e, th e p ro cess is n o t typi cally us ed becaus e t here are oth er m o re effi ci ent m et hods of t ransmis sion sign alin g

Th eref o re, sp read sp ect ru m t ransmi ssio n si gn alin g i s alm os t alw ays asso ci at ed with RF Th ere is alw ays a point at which th e

Sp read Sp ect ru m R adio sy stem mus t int erf ace with an oth e r

t rans missio n m edi um , and /o r sy st em This is acco mpli sh ed b y

co nv erting from RF to a wi reline signalin g p rotocol Th e telecomm uni catio ns p ro cess can b e vi ew ed as an excellent ex amp l e

Th e ch apt er is di vided int o s ectio ns t hat cov er

• T ran smissi on M edia

• T ran smissi on Sig na lin g

• Ba sic T el ep ho ne S e rvic e

• Multiplexi ng

• Hi gh C ap aci ty and B ro adb an d T ra nsmissi on

Sub-t opi cs in th e s ecti ons lo o k at:

• Me dia C onsid e ra ti on F a cto rs (why us e o n e ov e r an oth e r)

• Diff eren ce s b etw een v oi ce and da ta signalin g

• Vid eo T ra nsmis sio n (COD ECS & Comp re ssi on)

has it s place in t he d esi gn of

any commu ni cati on syst em E ach

has charact eristi cs whi ch will

make it t h e ideal m edium t o use

bas ed on a p arti cu lar set of

ci rcumst an ces It is impo rt ant

to reco gni ze t h e adv ant ages o f each and dev elop a system accordin gly

Tran smissi on effi ci en cy is gen erally vi ewed as th e am ount o f sign al d egrad ati on creat ed b y th e us e of a p arti cu lar t ransmissi o n mediu m Th e t ransmi ssion mediu m p res ent s a “b arrier” t o th e

co mmu nicati on si gn al The “barri er” can b e m easu red by man y diff erent f acto rs Howev er, one co mmo n qu esti on is as k ed abou t all co mmuni cati on m edi a Ho w far will t h e com muni cati o n signal

en ergy t rav el b ef o re it becom es t oo weak (o r dis to rt ed) to b e

co nsid ered uns ab le? Th ere i s equip m ent av ailab le t o ex ten d th e distance fo r t ransmit tin g a sign al, bu t t hat adds t o t h e ov erall

Factors to consider when choosing transmission media include: cost, ease of install ation and maintenance, availability, and most important, efficiency of transmission

M EDIA C O NSIDERATIO N F ACTO RS

Eas e of in stallation o f th e com muni catio n medi um is relativ ely simple to d efin e Gen erally , all com muni catio n m edia requ i re care when bein g inst alled The in stallati on s hou ld be acco mplish ed by

t rain ed and kn owled geable techni ci ans and m an agers F o r

pu rp os es o f this di scu ssio n, co nsid er th e relativ e d egree o f diffi cu lty fo r th e p lacem ent of th e t ran smissi on m edium C ables (fib er or cop per) requi re a supportin g i nf rast ru ctu re, as d o es radio o r inf ra red Co nsid er t he fo llowin g:

If yo u are p lannin g t o use f iber opti c (o r copp er cab le) and th e syst em plan calls fo r crossi ng t he D elaw are Riv er, t here will b e signi fi cant inst allati on (con st ru ctio n) challen ges Th e

co nst ru cti on m ay requi re a bo re un der t h e riv er, o r findin g a suitable b rid ge Eit h er of t h es e m et hods may add si gni fi cant ly t o you r bud get Wi reles s mi gh t s eem li ke a go od op tion I t eli min at es th e n eed to fi nd a suit ab le cros sin g lo cati on fo r you r cab le However, y ou will n eed to p lace t he an t enn a at s uffi ci en t hei ght to clear t rees bui ldin gs and ot her o bj ects , an d accou nt f o r terrai n dif f erences on b oth sides of th e riv er Local resi den ts o f

th e n earb y Yacht C lub cond o miniums may comp lai n abo ut th e radi o tower spoi lin g th ei r vi ew of t he sun set D on’t f o rget to ad d in t h e cos t of hi rin g a graphi c artis t to creat e a d rawin g t h at sh ows how lov ely th e ray s of t h e sett ing su n are w hen ref lect ed off t h e radio t ow er

Som e p ro du cts m ay b e m o re

readi ly av ailable t h an oth ers

Fo r ex amp le, th e m os t

co mmo n typ e of fi b er cab le

avai lab le is out sid e plan t

with arm o r s hi eldi ng, 9 6

st rand s o f sin gle m od e fi b er

array ed i n lo os e buf fer tub es, on 15 ,0 00 f oot reels M ake certai n that y ou allow en ou gh tim e fo r p ro du ct to b e manu factu red , esp ecially if a sp ecial cable o r h ardware con fi gu ratio n i s requi red Av ai labili ty o f p ro duct du e t o m anu factu ri ng d elays wi ll impact on ov erall p roj ect s ch edu le and may imp act on ov erall

p ro ject costs

Cab les th at co nt ain com bin atio ns o f dif feren t typ es of fi be r

st rand s su ch as sin gle m od e and mu ltim od e fi b ers, o r mi x tu res of copp er and fi ber, o r od d (diff erent f ro m s tandard put-ups )

“Put -ups” – the term ca ble manufact urers use to describe t he configuration of a cable The expression is often used in the following manner: “The cable is available in 5000 foot “put -ups ”

numb ers of fib er st rands wi ll requi re mo re tim e to p ro duce an d cou ld add s ev eral mo nth s to th e d eliv ery cy cle

Fib er, copp er, radio , inf ra red a ll hav e dif f erent t ra n smissio n

ch aracteris tics Fib er is consid ered to hav e t h e b es t overal l

ch aracteris tics fo r t rans mission ef fi cien cy That is, th e

ef f ectiv e lo ss o f signal st re ngt h ov er dist an ce C ab le is rat ed b y

th e m anu f actu rer fo r signal loss Signal lo ss f act o rs are s tat ed i n terms of d B per 10 00 m et ers Typi cal sin gle m od e fi ber may h av e

a si gn al att en uation f act o r o f b etw een 0 25 d B/km an d 0 5 d B/km

Th e cable m anu f actu rer wi ll p rovid e a sp eci fi cati on d es criptio n

fo r each p ro duct t h ey o ff er In th eo ry, you can s end a si gn al

fu rth er o n fi b er th an via mo st ot h er t ransmis sion m edia

How ev er, consid er t hat rad io signals at v ery low fre quen ci es (below 5 00 ki lo h ert z) can t ravel f o r th ous ands o f miles This t yp e

of radio si gn al can b e us ed t o carry d at a, but v ery i mp ractical fo r use in t raffi c si gn al and f reeway man agem ent sy st ems VLF radi o sign als are o nly capab le of ef fici ently carryin g d at a at very lo w bit rates This typ e o f sys t em w as us ed by th e Ass oci at ed P res s

o rgani zati on to t rans mit new s arti cles b etw een Eu rop e an d No rt h

Am erica, and is als o u sed by th e Mili tary f o r v ery lon g distan c e dat a com muni catio ns

Mai ntenance and op eratio nal costs are two other fact ors th at shou ld b e co nsid ered wh en comp ari ng t ran smissi on m edi a fo r an y giv en app li catio n Fib er opti c cable can b e ins talled in co n duit six feet b elow grad e, and n ever tou ch ed fo r d ecad es M aint enan ce o f

th e fi ber cab le is mini mal Microw av e syst ems m ay b e con st ru ct ed

in less tim e and at a lower cost t h an fi b er cab le placed i n

co nduit , but th e t ow er sites requi re signifi can tly mo re main tenan ce, i ncludi ng re-painti ng th e tow er, and an nua l inspecti ons fo r ru st

In s umm ary , t ake all of th e att rib ut es of th e p ot enti al m ed i a that cou ld b e us ed fo r a specifi c appli catio n and d et ermi ne whi c h will p ro vid e t he mo st “b an g fo r t h e bu ck” This do es no t alway s mean mos t b andwid th , high est t ransmissi on speed , easiest t o install, o r lowest co st - all f acto rs th at m ay i nf lu en ce y o u r choi ce

of t ransmis sio n media Th e best m edi a are t he on es that will suppo rt as many o f t h e sys t em requi rem en ts as p ossib le and h elp

to assu re s atis facti on wit h o verall p erfo rm ance

W IREL INE M ED IA

We b egin wit h b asi c in fo rm ation ab out th e m ost comm on types o f

t rans missio n m edi a us ed tod ay:

• Copper Wi re

• Fib e r Opti cs

• Radi o F requ en cy ( Wi reless)

• F ree Sp ace Opti cs

Many engi n eers will argu e t hat on e t ran smissi on m ediu m is th e bes t , or bett er t h an so m e of th e ot hers Th e read er sh ould keep

in mind th at each m ediu m has adv an tages and disad vant ages Whi ch m ediu m is b es t d ep ends upon th e pu rp os e of t h e

co mmu nicati ons sy st em and t he d esi red end resu lts In f act , mo s t syst ems are a hy b ri d Th at i s, tw o o r m o re m edi a are co mbin ed t o

ef f ect t h e m ost effi ci ent co mmuni catio n n etwo rk i nf rast ru ctu re

Th ere are many t raf fi c si gnal sys t ems th at combi n e a twist ed copp er pai r inf rast ru ct u re with wi reles s lin ks to s erve part o f

th e sys tem Th e d ecisio n t o creat e this typ e o f sys tem may h ave been based on eco nomi cs , bu t th at is cert ain ly on e o f th e reas on s

to ch oos e on e medi um ov er an oth er, o r to combi n e t h e us e o f sev eral

Copper Media

Th e elect ri cal p rop erties of copp er wi re create resi st an ce an d interf eren ce The fu rt her commu nicati on si gn als t rav el th e mo re

th ey are w eaken ed by t h e elect ri cal p ro p erties asso ci at ed wit h

th e copp er cable Elect ri cal, resist an ce wit hin t h e copp er m ediu m slows dow n t h e si gn al o r flow of cu rren t Th e elect ri c al

p rop erti es of copp er wi re are t h e key f acto rs t h at li mi t

co mmu nicati on t rans missio n speed , and dist an ce How ev er, it was tho se s am e p rop erti es t oget her wit h cost , eas e o f manu factu re , abi lity to b e d rawn int o v ery thi n s t ran ds , and ot h ers t hat m ad e copp er a lo gi cal ch oi ce fo r its selectio n as a com m unicati o n

t rans missio n m edium , an d a condu cto r of elect ri city Alu minu m and gold are also us ed f o r commu nicati on pu rpos es , but go ld ( th e most effi ci ent) is t oo exp ensiv e to us e f o r thi s pu rpos e an d alu minu m is no t an effi cient condu ct o r fo r co mmu nicati o n

pu rp os es

Th ere are two p ri mary t yp es o f cab les con tai nin g cop per wi re

• Twist ed P ai r

• Coa xia l

Twi sted Pair

Commu ni cati on si gnals s ent o ver copp er wi re are p rim arily di rect

elect ri cal cu rrent (D C) w hich is modu lat ed t o rep res ent a

f requ ency An y ot her elect rical cu rren t n ear t he co mm unicati o n

wi re (in clu din g ot h er com muni cation signals) can in t rodu ce interf eren ce and n oise Mu ltiple comm uni catio n wi res within a

cab le bun dle can in duce i nt erf erin g elect ro-m agn eti c cu rrents , or

“cro ss-t alk” Thi s h app en s w hen on e si gn al wit hin th e cable is so

st ron g th at it int ro du ces a magn eti c fi eld into an ad jacent wi re ,

o r com muni catio n p ai r E n ergy sou rces su ch as pow er t ran smissio n

lin es , o r f lu o res cen t lighti n g fixtu res can cau se elect ro magn eti c

interf eren ce This i nt erf erence can b e mini mi zed by tw istin g a

pai r o f wi res a ro und a c om mon axi s, o r b y t he us e o f metalli c

shi eldi ng, o r b ot h Th e twis ting ef f ectiv ely creat es a magn eti c

shi eld th at h elps to minimi ze “cross talk”

Twist ed p ai r is t h e o rdi nary cop per wi re t hat p rovi d es basi c

telep h on e s ervi ces t o t h e h o me an d m any busi n ess es In f act, it i s

ref erred to as “P lain Old Teleph on e S ervi ce” (P OTS) Th e twisted

pai r is comp os ed of two in sulat ed copp er wi res twist ed around on e

an oth er Th e twistin g is d on e t o p rev ent opposi ng elect rical

cu rrents t rav elin g alon g th e individu al wi res f ro m int erf erin g

with each ot her

Twist ed copp er p ai r, is w hat Alex and er Bell us ed to m ake t h e

fi rs t t elep ho ne s yst em w o rk and i s gen erally t h e mo st co mmo n

t rans missio n m edium u sed to day

A b ro a d g ene rali zation is that twisted copp er pai r i s in fact

th e b asis fo r al l telecomm uni catio n t ech no lo gy and s ervi ces t oday Et h ern et –

o ri gin ally developed to w o rk ove r

co axi al cable - is no w a stan dard b as ed on twist ed pai r

By comp aris on , a basi c v oic e telep h on e con vers ati on u ses on e (1) twist ed p ai r, w h ere as an Eth ern et s essi on us es at leas t

F i g u r e 2 - 1 : R J - 4 5 C o n n e c t o r

Eth ern et lat er in t his ch apt er)

Each conn ecti on on twis t ed pai r requi res bo th wi res Since s om etelep h on e sets o r des kt op lo catio ns requi re mu ltip le co nn ectio ns , twisted pai r is s om etim es installed in two o r mo re p ai rs, al l within a si ngle cab le Fo r so me bu sin ess lo cation s, twis ted pai r i s

en clos ed in a s hield th at f u ncti ons as a gro und This is known as shi eld ed twis ted p ai r ( STP) Ordin ary wi re to t h e hom e i s unshi eld ed twist ed p ai r ( UTP) Twist ed p ai r i s now f requ en tly installed with two p ai rs to t he ho m e, wit h t h e ext ra pai r m aki n g

it possi ble t o add an oth er lin e - p erh aps fo r m od em u se

Twist ed p ai r com es wit h

each p ai r u niqu ely co lo r

cod ed wh en it is p ackaged

in multip le pai rs

Diff erent us es su ch as

an alo g, di git al, and

Eth ern et requi re

diff erent p ai r m ultip les There is an E IA/TIA s tandard f o r colo r codi n g of wi res , wi re p ai rs, and wi re bund les Th e co lo r codi n g allows t echni ci ans to i nst all syst em wi rin g in a s tand ard man n er

A b asi c sin gle t elep ho ne lin e in a ho me wi ll us e t he red and gree n

wi re If a second ph on e li n e is p rovid ed , it will us e th e y ellow an d black wi re Th e mo st com mon

caus e o f t elecommu ni cat ion

syst em p ro blem s is inco rrect

wi rin g Thi s wi ri n g p rot o co l is

fo r st an dard t eleph on e set

jack con necti ons D at a sy st ems

use di ff erent arran gements

and co lo r codes Th e m ost co mmo n is t he EIA/TIA s tand ard Pleas e n ot e t h at NE M A and ICE A have co lo r cod es fo r elect ri c al

wi re D o n ot con fus e th es e with telecom muni catio n wire colo r codi n g st and ards

Twist ed pai r is cat ego ri zed by th e numb er o f twists p er m et er A greate r numb er of twist s p ro v ides mo re

p ro tecti on agai nst cro sst alk , and oth er

fo rms o f int erf eren ce and resu lts in a bett er q uality of t ransmi ssi on F o r d at a

t rans missio n , b ett er qu ality equ at es t o

Cat 3 cable is considered to be the standard for basic telep hone and Ethernet services However, CAT 5 is being deployed as a replacement and in all new installations

EIA/TIA provides a color code and wiring standard for R J-45 Connectors The standard is EIA/TIA 568A/568B These standards utiliz e 4 twisted pair, because the R J-45 connector has 8 terminals

F i g u r e 2 - 2 : Tw i s t e d P a i r C a b l e

ef f ects o f t ransmis sio n erro rs as t hey imp act on th ro u ghput an d delay tim es

Th ere are tw o typ es of twisted pai r cab les us ed f o r most i buildi ng situ ati ons to day - C at ego ry 3 UTP (C AT 3) and Cat ego ry

n-5 UTP (C AT n-5) However, as of t h e w ri tin g o f t his h an d boo k, all new and replacem en t inst allatio ns us e C AT 5 Th es e cables hav e been developed b as ed o n a s et of st an dards i ssu ed by t h e EIA/TIA ( Elect ro ni c Indus t ry Ass o ciati on /Telecom mun icatio n s Indu st ry Ass o ciati on) C AT 3 is us ed p ri mari ly fo r t elep ho ne cab lin g and 10 Bas e-T inst allations , whi le C AT 5 i s us ed t o suppo rt 10/1 00 Bas e-T i nst allatio ns C AT 5 wi rin g can als o be u sed fo r telep h on e syst em s Theref ore, mos t new ins tallati ons us e C AT 5 inst ead of C AT 3 Th e C AT 5 cab le i s pulled t o a cubi cle o r of fi ce and con nect ed t o a u niv ersal wall plat e th at allows f o r installation of data and voi ce com muni catio n syst ems C at ego ry 5E (C AT 5E) has b een d ev elop ed to accomm od at e Gi gE i nst allatio ns

C AT 5E is manuf actu red and tes ted und er st ricter guideli nes th an

C AT 3 o r C AT 5 Two n ew s tand ards – C AT 6 and C AT 7 - h av e been adopt ed to m eet crit eri a fo r 1 0 GigE ( and hi gh er)

t rans missio n sp eeds

Ta b l e 2 - 1 : Tw i s t e d - P a i r C o m m u n i c a t i o n C a b l e C a t e g o r y R a t i n g s

Category Maximum D ata Rat e Usual App lication

CAT 1 Less than 1 Mbps Analog Voice (POTS), Basic

R ate ISDN, Doorbell wiring

Networks CAT 3 16 Mbps

Voice and Data, and 10Base-T Ethernet Basic telephone service

CAT 5 100 Mbps up to 1

Gbps

10Base -T, 100Base -T (fast Ethernet), GigE, FDDI, 155 Mbps ATM

CAT 6 Greater than 100

Mbps

Broadband Applications CAT 7 Emerging Standard GigE plus

Coaxial Cable

Coaxial cabl e is a p rim a ry ty pe of copp er cab le used b y cab le T V

co mpanies fo r si gn al dist rib ution between t h e com munit y ant en n a and us er hom es an d busi ness es It w as o nce t h e p ri mary mediu m

fo r Et h ern et and

other t ypes of local

area n etw orks Wit h

th e dev elop m ent o f

on e phy sical ch ann el

(th e co pper co re) th at carri es th e signal su rrou nded (aft er a lay er of insulati on) by another co ncentric ph ysi cal channel ( a metalli c foi l or braid) , and an outer cov er or s heath, all runni ng alon g t h e s am e axis Th e o uter chann el s erves as a s hield ( o r grou nd) Many o f t h es e cab les o r p ai rs of co axi al tu bes can b e placed i n a si n gle condui t and , wit h repeat ers , can carry info rm ati on f o r a great dist an ce In fact , t his typ e of cab le was used fo r hi gh b andwidt h and vid eo servi ce by t h e t elep ho ne

co mpanies p rio r t o t he i nt ro d ucti on of fib er in t h e 19 80’ s

Th ere are s ev eral v ari ati ons Tri axi al ( Tri ax) is a fo rm of cabl e that us es a si n gle cent er co ndu ct o r with two s hi elds Thi s

co mposi tion af fo rd s a greater t ransmi ssio n dist an ce with les s loss du e t o i nt erf eren ce f ro m ou tsid e elect ri cal signals Twinaxia l (Twin ax) is tw o co axi al syst ems packaged wit hin a sin gle cab le

Insulation

Metallic Shield (can

be foil or braided)

Outer Sheath

Copper Core

F i g u r e 2 - 3 : C o - Ax i a l C a b l e I l l u s t r a t i o n

Coaxial cab le was in vent ed in 1929 and fi rs t us ed comm ercially i n

1941 AT& T estab lish ed i ts fi rst cro ss- co ntin en tal co axi al

t rans missio n sys t em in 1 94 0 Dep endi ng on th e carri er t ech no lo gy

used an d ot h er f acto rs , twis ted p ai r copp er wi re and op ti cal fib er

are alt ern ativ es t o co axi al cable

Coaxial cable was o ri gin ally used by so m e t raffi c d epart ments t o

p rovide com muni cations b etw een field co nt ro llers and t he cent ra l

co nt ro ller in an aut om at ed t raffi c si gn al syst em It was als o t h e

mediu m o f ch oi c e f o r earl y implem e nt atio n o f vid eo incid ent

man agem ent sy st ems us ed in ITS How ev er, wit h th e int rodu ctio n

of fib er opti cs , th e us e of coaxial cab le h as all b ut be en

ab and on ed fo r t his pu rp os e

Coaxial cab le is still us ed fo r co nn ectin g CCTV cam eras t o

monit o rs and vid eo switch ers As t h e cost of usi ng fib er opti cs

has b egun to d ro p, cam era man uf actu rers are in st alli ng fib er

opti c t rans ceiv ers i n t h e cam era This is esp eci ally us efu l fo r

p rev enti ng i nt erf eren ce f ro m elect ri cal syst em s, o r creatin g a

secu re vid eo t ran smissi on netwo rk

Fiber Optics & Fiber Optic Cable

Fib er op tic (o r "op tical fi b er") refers t o t h e m ediu m and th e

tech no lo gy ass o ciated wit h th e t ransmis sion of in fo rm atio n as

light i mpu ls es alon g a s t rand o f glass A fi b er opti c st ran d

carri es mu ch mo re info rm ati on th an

co nv enti on al copp er wi re and is far less su bj ect to

elect ro m agn eti c interf eren ce ( EMI) Almos t all teleph on e lon g-di st an ce (cro ss cou nt ry) lin es are now fib er opti c

Tran smissi on ov er fi ber op tic st rands requi res rep eating ( o r

regenerati on) at v aryin g in terv als Th e spacin g between t h es e

interv als is great er (po t enti ally m o re th an 1 00 km , o r 5 0 miles)

than copp er based sys tems By co mparis on , a hi gh speed elect ri ca l

sign al su ch as a T-1 si gnal carri ed ov er twist ed-p ai r must b e

Core

Cladding (Refractive Coating) Cover

F i g u r e 2 - 4 : B a s i c F i b e r O p t i c S t r a n d C o n s t r u c t i o n

Fiber op tic cable loss is calcu lat ed in d B p er kilom et er (dB/KM) ,

and copp er cab les are rated in dB p er m et er (d B/M) N ote: Th e App endix of this handbook includes an exp lanation of how to calculate a fiber op tic loss budget

Th e fi ber op tic st rand is const ru ct ed (s ee graphi c) in sev era l lay ers Th e co re is th e actu al glass , o r fib er, condu ct o r This is cov ered wit h a ref ractiv e co atin g – called claddin g - t hat caus es

th e li ght t o t rav el in a co nt rolled p ath alo ng t he enti re len gt h o f

th e glas s co re Th e next lay er i s a p rot ectiv e co veri ng t h at keep s

th e co re and co atin g f ro m sustai nin g damage It also p rev ents light from es capi ng t he as sem bly, and has a colo r co ding fo r iden tifi catio n pu rpo ses Th e co re, coatin g and cov ering are

co llectiv ely ref erred to as a “s t ran d” Fi ber st rand s izes are alw ays ref erred t o in t erms of t h e di am et er o f t he co re

Fiber Optic Cable

Fib er s t ran ds are typi cally bund led within a cable Th e st rand s can b e placed in a “ti gh t” o r

“loos e” bu ff er tu be array The

lo os e bu ff er tu be array is t he

most co mm on ly dep loy ed fo r

outsid e plan t appli cati o ns

Tight bu ff ered cab le is

gen erally us ed wit hin a bui ldi ng

fo r ris er and h o ri zon tal cable Ti ght buf fer cab le is als o used fo r

an “in do o r/outd oo r” appli cati on Thi s cab le is co nst ru ct ed with a weath er/mois tu re resist ant cab le sh eat h , and i s gen erally us ed t o get f ro m a sp li ce bo x lo cat ed wit hin s ev eral hund red f eet o f a buildi ng uti lity ent ran ce, an d must b e ru n s ev eral hund red f e et within a buildin g to t h e mai n fiber dis t ri buti on poi nt If th e mai n fib er dist ri buti on p oint is less th an 10 0 f eet f ro m t h e bui ldin g ent ran ce, th ere m ay b e n o advan tage to u sin g th e in do o r/ou tdo o r cab le

Fib er s t ran ds are placed in a large ( relati vely) di am et er t ube an d allow ed t o “float” wit h consi derab le m ov em en t As t h e fi ber cabl e

is pulled int o place (in cond uit, di rectly bu ried, o r p laced o n a pole) th e st rands are not su bj ected t o t h e fo rces of th e pu llin g ten sion Th e st rands th eref o re sust ain minim al damage o r disto rti on f rom s t retchin g

I n s i d e p l a n t c a b l e i s c o n s t r u c t e d

t o b e f l e x i b l e a n d l i g h t w e i g h t T h e

c a b l e m a y b e c o a t e d t o m e e t f i r e

p r o t e c t i o n c o d e s

Fiber cables are ( as are all co mmu nicati ons cables) m anu factu re d bas ed o n th ei r int end ed us e Each cable will h av e a st an dard se t

of marki n gs i ndicati ng its

p rim ary us e, t h e n am e of t he

man uf actu rer a N ati o nal

Elect rical Co de rati n g and a UL

app rov al cod e, t h e num b er of

fib ers co nt ain ed wit hin t he

cab le, th e ou tsid e di am et er of

th e cab le, and t he

man uf actu rer’ s p rod uct

nom en clatu re All of th es e items sh ould b e checked when t h e cable is d elivered to a storage area and t h en at th e job-sit e befo re t h e cable i s ins talled Generally , fi ber cables fall into on e

of t h e f ollowi ng classifi cati o ns:

Som e cables are manufactu red wi th a m et alli c arm o red s heat h t o

p ro vide ad ded st ren gt h an d p rot ectio n again st ro den ts Fi be r cab le th at is p laced i n u nd ergro und cond uit , is no rm ally filled with a waterp ro o f gel co mpoun d Out sid e plant cables are gen erally m anu fact u red with a gel fillin g in th e buf f er t ubes an d

a wat er b lo cki ng t ap e b etw een t he i nn er and out er jackets Bo t h out er and i nn er j ackets are m ad e of m at erials d esi gn ed t o withst and i mm ersio n and resi st co rro si on

Fib er st rands and cab les are manuf actu red wi th a st and ard colo r codi n g This p ermits ef f ecti ve m an agem ent of cab les b ecaus e of

th e n o rm ally hi gh st rand co unts cont ain ed wit hin a cab le Th ere are 2 4 colo r co mbi nation s used A lo os e buf f er tu b e cable wit h

57 6 st rands w ould h av e 2 4 tub es co lo red as in dicat ed in th e

ch a rt b elow Wit hin each bu ff er tub e wou ld b e 24 fi b er st rand s using t he sam e

Central Strength Member

Outer Jacket

Armor (Corregated Steel,

or Aramid Fiber)

Buffer Tubes

Filler Material

F i g u r e 2 - 5 : F i b e r O p t i c C a b l e I l l u s t r a t i o n

2 2 V i o l e t / B l a c k T r a c e r

Another aspect of fiber construction is the actual size of the

a com bin atio n o f th e fib er co re and it s claddin g Mos t m ultim od e cab le u sed tod ay h as a co re diam et er o f 6 2 5µm and m o st sin gl e mod e fi b er h as a co re di amet er of 9µm Therefore, th e fi b e r

st rand si ze wi ll n o rm ally b e list ed as 6 2 5µm/125µm fo r multi mod e and 9µm/1 25µm f o r sin gle m ode fib er

Th e st rand di am et er i s kept consis t ent to h elp w ith t h e man uf actu rin g and i nst allat ion p ro cess es Th e co re d iam et e r varies becaus e o f diff ere nces in so me o f th e t ransmissi o n

ch aracteris tics of t he fibers When pu rchasi n g fi ber cable t o b e add ed to an exis tin g s yst em , make cert ai n t hat s t ran d diam et e r and th e co re di am et ers match Fusi on spli cin g ( see chap t er 8 fo r

an exp la na tion of s pli cin g) f ibers wit h dif f erent co re di am et ers

is possi ble How ev er, th ere will p ro b ab ly b e a mi sali gnm ent t ha t

is th e caus e of po o r sys tem perf o rman ce If you must us e fib ers with dif f erent co re di am et ers it i s b es t t o us e a m ech ani cal spli ce to assu re p rop er ali gnm ent N ev er s pli ce mu ltim o de fi b er

to sin gle m od e fi ber If y ou must place sin gle m od e an d m ultim od e

in t he s am e syst em us e a “m ode co nv erter” to f acilit at e th e

t ransi tion

Fiber Cable Types

Fib er cab les are p ro du ced in two b asi c f o rms:

• Lo os e Tub e Buf f e re d Ca bl e

• Tight Bu ff ered Cabl e

Lo os e tub e cab les are p ri marily us ed in outsid e plant app licatio ns

Th ey are d esi gned to p ro t ect th e fi b ers f ro m damage (st ret chi n g and kin ki ng) th at mi ght res ult

f rom an overly aggressiv e cable

puller Th e tub e arran gem ent

als o allows f o r eas ier

t ransi tion to fib er d rops at

buildi ngs o r commu ni cat ion

cabin et s Th e fi ber st ran ds

float within th e bu ff er tu bes

and are n ot part o f t h e cable

st ru ct u re Lo os e tu b e cab les

a re id e al fo r m et ro po lit an a nd

lon g di st an ce cable in stallati ons

Tight buf f er cables are sp ecifi ed fo r in side plan t us e Th es e types of cables are d esi gn ed f o r us e within a cont ro lle d envi ro nm en t su ch as a bui ldi n g o r insid e plan t equip m ent cabin ets Becaus e t h e cab le i s us ed wi thin a buildi n g t he cab le it requi re s less ph ysi cal p ro tecti on an d has great er f lexibi lity Th e fi b ers within t he cab le are sus cept ible to d amage f ro m aggressi ve cabl e pulls b ecaus e t h e fib er st ra nds are p art o f t he cab le s t ru ctu re

Th e st rands are ti ghtly b oun d in a cent ral bu nd le withi n t he ou t e r cab le sh eath

Fib ers are ass em b led int o eit h er st rand ed o r rib bo n cables

St randed cab les are individ u al fi b ers th at are bund led t oget h er Rib bon cable is cons t ruct ed by groupi ng up to 1 2 fi bers and

co ati ng th em wi th p lasti c t o fo rm a m ulti fib er rib bo n St randed and ri bb on fib er b und les can b e p ackaged to get her i nt o ei th e r

lo os e o r ti ght b uf feri ng cab le

accommodate buffer tubes

Fibers protected from cable pulling

forces

Fibers sensitive to pulling forces

Used primarily for outside plant Used for inside plant and

distribution

Fiber Strand Types:

Fib er st rands are p rodu ced i n two b asi c vari eti es: Mu lti mod e an d Sin gle m od e E ach v ariet y is used to faci litat e specifi c requi rem ent s o f th e commu ni catio n syst em

Multimo de is o pti cal fib er t h at is design ed to carry mu lti ple ligh t rays o r m od es con cu rrent ly , each at a sli ghtly d iff eren t ref lection an gle within th e opti cal fi ber co re Mu ltim o de fi b er

t rans missio n i s us ed f o r relativ ely s ho rt dis tances b ecause th e mod es t en d to di spers e ov er lon ger lengths (thi s is called mod al dispersi on) Multim ode fib ers hav e a core diameter of b etween 5 0

& 200 mi cro ns Mu ltim od e fi ber is us ed fo r requi rement s of les s than 15 ,0 00 feet Mu lti mod e fi ber becam e avai lable du rin g t h e early 1 98 0’s and is sti ll b ei ng u sed in many o ld er sy st ems Wit h

th e adv an ces in fi ber t ech nolo gy and th e nu mb er of p rod uc t

ch oi ces av ailab le, mu lti mod e fib er i s almos t nev er d eployed fo r new syst em s Th ere are mechanical d evi ces av ailab le t hat accomm od at e a t ransiti on f ro m multim ode fib er to sin gle m od e fib er Mu ltim od e fib er i s generally “lit ” with LED ( Li ght Emitti n g Diod es) whi ch are less expensiv e th an LASE R t ran smitt ers Multimo de fib er is gen erally manu f actu red in two si zes 50µ m an d

62 5µm

Sin gle m od e is opti cal fib er that is d esi gn ed f o r th e t ran smissio n

of a sin gle ray o r mod e of ligh t as a carri er Sin gle m o de fib e r has a mu ch sm aller co re t han mu ltim od e fi b er Si ngle m o de fib e r

is p ro duced i n several v ari at ions Th e v ari ati ons are desi gn ed t o facili tate v ery lon g dis tances , and t h e t rans missio n o f multip l e light frequ encies wit hin a si ngle li ght ray F ollowing ch ap ters wi ll discus s t rans missio n sy st em cap abiliti es – S ee: E th ern et , SONE T and D WD M Si ngle m od e fi ber is gen erally m anu factu red wit h

co re di am et ers between 7 an d 9 mi crons