Central Office Concepts

Central Office Concepts High Level Overview Introduction to Telephony Basics Created by: Eddie Phillips Revision date: 6/2002 Verizon Course # YYJ8166 1

C.O. Concepts - Table of Contents Slide Topic Purpose 7 Purpose of High Level Overview Introduction 9 Telephone Services 10 POTS Plain Old Telephone Service 11 Special Circuits Generic Types 21 Special Circuit Overview 23 Sound versus Frequency 25 Analog lines, Digital trunks 26 Converting an Analog signal to Digital 27 Filtering, Sampling & PAM 29 PAM Pulse Amplitude Modulation 30 Quantizing Error 31 PCM 32 Voice to PAM to PCM 2

Table of Contents (Continued) Slide Topic Data Rate Overview & low bit-rate circuits 33 Why Digital? 34 Effect of Noise 36 Digital Signal Rate 0 DS0 37 Data Rates - DS0,, DS3 39 Time Division Multiplexing TDM 43 - Digital Signal Rate 1 47 Uni- and Bi-polar signals 51 B8ZS - Binary 8-bit Zero Substitution 53 DS3 Multiplexer 55 DS-30 format 58 Lines versus Trunks 59 Signaling 63 Robbed-bit Signaling 68 Extended Superframe ESF 70 ISDN BRI 73 ISDN PRI 76 Central Office Layout 77 Main Distribution Frame 79 MDF - Pair protection 3

Table of Contents (Continued) Slide Topic 89 DSX-1 cross-connect 96 D4 channel bank 100 Dual Ringing Generators 102 Special Circuits 108 ISDN channel bank 112 Digital Cross-connect System - DCS 115 DCS 1/0 - input/ds0 cross-connect 122 DCS Functional types 126 Hi-cap circuit 127 versus T1 129 Line Termination Shelf 130 T1 Repeater Housing 133 Repeater Housing Symbol 134 T1 Repeatered Span Line 137 HDSL 143 Fractional T1 () 147 DSX-3 Cross-connect 153 M13 Asynchronous Multiplexer 148 Fiber Systems - Asynchronous 159 Fiber Optic Systems interoffice components 4

Table of Contents (Continued) Slide Topic 166 SONET Fiber Optic Systems 169 SONET Hierarchy & Rates 173 SONET Rings - UPSR 174 SONET Rings - BLSR 176 Fiber Cable Termination - LGX 189 Tracing an FX circuit through an office 190 Wave Division Multiplexing 193 Dense WDM 196 Wideband DCS 199 Broadband DCS 201 Microwave Radio 208 Digital Loop Carrier (DLC s) 218 MDF in DLC s Equipment protection 5

Table of Contents (Continued) Slide Topic 220 ADSL 231 Timing 242 Power Diagram 249 Main Power Board feeding Trans. Dist. Power Board 253 Batteries 256 Generator 257 AC Transfer Switch 258 Grounding - protection from lightning, etc The pictures on this page are of antique operator cordboards. 6

Central Office Concepts Purpose: To provide an high level overview of the signal formats, circuits and equipment types that are found in a typical telephone office. 7

Central Office Concepts Overview - Part One Telephone Services - POTS Vs. Special Circuits Analog to Digital Conversion Data Rates - DS0,, DS3 Main Distribution Frame DSX-1, DSX-3 Jacks D4 Channel Bank ISDN Banks DCS 1/0 - Digital Access Cross-connect System 8

Telephone Services ISP CLEC IXC Operator Special Circuits POTS CLASS Telephone Office PBX Centrex ADSL ACD Automatic Call Distribution Hi-caps Call Center 9

POTS Plain Old Telephone Service 2 wires, 1 pair Telephone Office Voice Signal Maximum distance from telephone office 18,000 feet. Under 12,000 feet is preferred. 10

Special Circuits Everything Else but POTS Overview of Generic Types Central Office Analog Phone ISDN phone Utility company circuit Computer circuits To distant office To ISDN line circuit Alarm & control circuits Digital Circuits Personal Computer Hi-cap to Network To Internet To customer s network 11

POTS & Special Circuits Telephone Office POTS Phone line Digital Switch Phone line Special Circuits Analog Phone ISDN phone Utility company circuit Computer circuits Personal Computer Hi-cap to Network Trunk Transmission Equipment Network 12

Digital Switch Nortel DMS-100 13

Digital Switch - Automatic Electric GTD-5 14

Transmission Equipment 15

Transmission Equipment 16

Main Distribution Frame - terminates copper outside plant cables & equipment cables 17

Copper outside plant cables 18

Copper cable splice closures in vault 19

Fiber Optic cable & jumper termination 20

Special Circuits Overview 3 Broad Categories Voice-grade circuits Foreign exchange - draws dial tone from a foreign office Analog Data circuits - non-digital ex. Circuits for real-time measurements; pump starting, water levels, door open/close etc. Digital Data circuits digital circuits, ISDN, hi-caps, etc. 21

Introduction Summary What a telephone office does: POTS normal 7 or 10 digit dialing for calls we make everyday. Special Circuits unique circuits requested by the customer to meet a specific customer requirements. 22

Sound versus Frequency Frequency - Electrical representation of sound Sound Waves - unit of measure is Hertz or cycles per second Human ear - 20-10,000 Hertz (and higher) Analog Signal - electrical signal analogous to real sound 23

How voice circuits go through the network POTS, Special Circuits Telephone Office Network Telephone Office Voice or Analog signal Digital signal - analog signal converted to a binary code - 1 s and 0 s. Voice or Analog signal 24

Analog lines, Digital trunks 1 0 1 1 0 1 0 1 Telephone Office Line Line Telephone Office 1 0 1 1 0 1 0 1 Digital Trunk Analog Signal Telephone Office Line 25

Converting an Analog Signal to a Digital Signal Analog Signal Digital Signal Binary digit or bit 1 0 1 1 0 1 0 1 1 - presence of a pulse 0 - absence of a pulse Binary 8-bit word or byte 26

Filtering, Sampling & PAM - Pulse Amplitude Modulation Original Voice Frequency Signal 20 Hz to 10,000+ Hz Low-pass Filter Output 20 Hz - 4000 Hz 8000 times per second (Hertz) sampling Measuring signal levels in real-time 125 microseconds 27

Voice signal voltage sampled at 125 microseconds intervals. - 8000 times per second Voltage T 0 T 1 T 2 T 3 T 4 T 5 T 6 T 7 T 8 T 9 Time 125 microseconds between measurements 28

PAM - Pulse Amplitude Modulation Voltage level compared to Quantization level Quantization Level 3-bit binary code 7-111 6-110 5-101 4-100 3-011 2-010 1-001 0-000 Decimal - Binary T 0 T 1 T 2 T 3 T 4 T 5 T 6 T 7 T 8 T 9 Time 29

Quantizing Error small distortion Quantization Level of signal 7-111 6-110 5-101 3-bit binary code 4-100 3-011 Quantizing Error 2-010 1-001 0-000 Decimal - Binary T 0 T 1 T 2 Time 30

8-bit Binary Code 11111111 128 PCM Pulse Code Modulation PAM pulse Each voltage level has a pre-assigned code 10000110 6 10000101 5 10000100 4 10000011 3 10000010 2 10000001 1 00000000 0 00000001-1 00000010-2 00000011-3 00000110-4 00000101-5 00000110-6 Maximum distortion Quantization error time 01111111-128 31

Voice Encoding Voice to PAM to PCM - 8-bit word Each PAM value converted to 8-bit word 125 microseconds PCM encoder 8000 samples/sec X 8 bits/sample = 64,000 bits/sec digital stream per voice channel 1 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 DS0 = 64,000 bits per second 8-bits 8-bits 32

Why Digital? Analog Transmission Noise Problems Analog Signal Signal Plus Noise After Transmission Attenuation Plus Increased Noise Amplified Signal Plus Noise 33

Effect of Noise Analog versus Digital Analog-only signal plus noise: Signal Noise Received Signal + = Digital Signal plus noise: Signal Encoded (PCM) Noise PCM + Noise Received Signal + = 34

Summary Analog lines, digital trunks Voice frequency: Filtered Sampled PAM Pulse Amplitude Modulation Quantized PCM Pulse Code Modulation 8-BIT word 8,000 times per second PCM 64,000 bits/second = 1 DS0 35

Digital Signal rate 0 - DS0 8-bit format - 64 kbs 1 0 1 1 0 1 0 1 1 2 3 4 5 6 7 8 125 microsecond interval per 8-bit word DS0 = 8000 8-bit words per second = 64,000 bits/second = 64 kbs Fundamental digital signal in telecommunications Building block of most of all other signals 36

Data Rates & Formats DS0-64,000 bits/sec (64 kbs) channel - digitized voice or data - 24 DS0's = 24 x 64,000 = 1.544 Mbit/sec DS3-28 's = 28 x 1.544 Mbs + overhead = 44.736 Mbit/sec - 672 DS0 s = 24 DS0 s x 28 s 37

Information is on leading edge 8-bit word represents a 125-microsecond sampling interval of pulse 8-bit word can occupy less time than 125 microseconds 1 0 1 1 0 1 0 1 1 2 3 4 5 6 7 8 Information is on the leading edge of the pulse. Same 8-bit word, but occupying less time. 1 0 1 1 0 1 0 1 1 2 3 4 5 6 7 8 Width of each pulse is squeezed to occupy less time so other circuits can be added in the same time frame. 38

Time Division Multiplexing - TDM DS0-64 kbs 1 The pulse widths of bits in the 24 channels are squeezed to put all 24 channels on one high-speed channel. 2 3 TDM - 1.544 Mbs 24 Bi-directional multiplexer. Only one direction is shown. Low-speed side High-speed side 39

Time Division Multiplexing TDM - 24 DS0 s into a Only one direction shown DS0 10101010 1 23 Channel 4 5 TDM TDM - Interleaved together in time. One frame = 24 channels X 8 bits/chan. + 1 framing bit =193 bits/frame Rate = 193 bits/frame X 8000 frames/sec = 1,544,000 bits/sec = 1.544 Mbs DS0 10101010 24 21 22 23 24 Framing bit DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 40 1

Voice to Digital to TDM 1 2 3 Analog to Digital Converter Time Division Multiplexer 24 channels multiplexed together in time. 24 41

A/D-Mux - TDM Demux-D/A 24 channels multiplexed together in time. 1 1 2 2 Time Time 3 Analog to Division Multiplexer Division De-multiplexer Digital to 3 Digital Analog Converter Converter 24 24 Only one direction is shown. 42

DS-1 Digital Signal rate 1 24 channels TDM + Framing bit Framing bit Frame 193 bits/frame DS0 s 24 1 frame is: 24 DS0 channels (64 kbs) plus one framing bit = 24 channels X 8 bits/channel + 1 framing bit = 193 bits/frame. Rate per second: 193 bits/frame X 8000 frames/sec = 1,544,000 bits/sec -OR- 1.544 Mbs. Framing Bit indicates the beginning of the frame. 3 2 1 43

Bits in a are Bi-polar Every other 1 bit is reversed in polarity bit stream 0 1 1 0 1 0 1 1 1 1 0 1 0 1 1 0 0 1 1 0 1 0 1 1 DS0 DS0 DS0 Max bit rate = 1.544 Mbs Max frequency = 772 khz 44

One 24-channel frame A has a signal going in both directions, a Transmit signal and a Receive signal 125 microseconds Framing Bit 8-bit channel 1 24 (24x8) +1 = 193 bits/frame 1 8 1 8 One 8-bit channel One 8-bit channel 45

One frame RX - Receive TX - Transmit 125 microseconds 24 8-bit words +1framing bit = 193 bits 24 8-bit words = 192 bits 1 24 Framing bit (1 bit only) 1 2 3 4 5 6 7 8 Least Significant Bit 7-bit word 8-bit word 46

Uni-polar & Bi-polar Signals Signals look different, but binary codes are the same Uni-polar signal 1 0 1 1 0 Bi-polar signal 1 0 1 1 0 47

Line Frequency of Uni-polar and Uni-polar signal Bi-polar signals 6 times crossing reference line A Bi-polar signal 1 0 1 1 0 3 times crossing reference line B 1 0 1 1 0 B has half the frequency of A 48

Bi-polar signals cut the effective Uni-polar signal frequency in half 6 times crossing reference line A Bi-polar signal 1 0 1 1 0 3 times crossing reference line B 1 0 1 1 0 Bipolar has half the frequency of Uni-polar 49

Bi-polar Signals Doubles digital signal distance on copper wire Uni-polar signal Distance Bi-polar signal 2 times Distance Cutting the frequency in half, doubles the distance the signal can travel 50

The Zero Problem B8ZS - Binary 8-bit Zero Substitution A code is substituted when all zero s appear. Flat line 8 zero s One 8-bit word with all 0 s 0 0 0 0 0 0 0 0 Rule: Every 8-bit word MUST have at least one 1-bit Solution: Substitute with B8ZS line encoding Bi-polar violation (by design) 8 zero s line code 0 0 0 1 1 0 1 1 51

Summary DS0 one digitized voice channel TDM combines 24 voice channels into a Mux multiplexes DS0 s together in time into a DeMux de-multiplexes DS0 s from a into individual channels. Binary digits in a digital bit stream are bi-polar Bi-polar signals have lower frequency & can travel further on copper wire. B8ZS substitutes a special code for eight zero s. 52

DS3 Multiplexer TDM - 28 s to 1 DS3-1.544 Mbs 28 s Low-speed side 1 2 3 4 5 6 7 8 9 10 Multiplex : 28 s to 1 DS3 DS3-44.736 Mbs DS3 Multiplexer High-speed side 26 27 28 De-multiplex : 1 DS3 to 28 s The pulse widths of the bits in the 28 s are squeezed to put all 28 channels on one high-speed DS3 channel. 53

DS3 Frame Format 24 DS0 channels for each 28 27 26 Header 5 4 3 2 1 DS3 rate = 44.736 Mbit/sec 28 channels plus DS3 framing 672 DS0 channels = (28 s X 24 DS0 s/) Bi-directional - TX and RX 54

DS-30 DS-30 Frame 193 bits/frame DS0 s 32 3 2 1 Like a, but with 32 channels instead of 24 channels; no framing bit used. 30 channels voice, 2 channels control European standard Sometimes used by switch vendors inside digital switches 55

44.736 Mbs Bit rate Comparison DS0,, DS3 DS3 28 s 2.048 Mbs 1.544 Mbs 64 kbs DS0 Digital voice 24 DS0 s DS-30 32 DS0 s 56

Central Office Switching Lines, Trunks Transmission connection between offices special circuits most anything else Switching & Transmission are blending together 57

Lines versus Trunks Trunk - connection from office-to-office Telephone Office Telephone Office Line - access from customer to the network Line 1 Trunk = one 2-path digital voice circuit = 1 DS0 Transmit & Receive on two separate facility paths 1 Line = one 1-path voice circuit Transmit & Receive on 1 cable pair - analog or digital connection 58

Signaling Signaling is the process by which two or more telephone offices communicate between each other to setup and take down a telephone call. Telephone Office Telephone Office Line Line 59

In-band Signaling from Telephone office to Telephone office A B Line Telephone Office Trunk Telephone Office Line A informs B of incoming call. B checks line for on-hook or off-hook condition. B informs A of status of line. B applies ringing to the line. When phone answers, voice path is created between A & B. If off-hook, a busy tone is sent from B to A. When a phone is again on-hook, path is dropped. 60

Signaling Calling-office to Called-office Line Telephone Office Telephone Office Line Digital Trunk - DS0 Robbed-bit Signaling is used to transfer signaling information from calling-office to called-office. Ex. when calling-phone goes off hook; sending dialed digits. 61

Signaling Called-office back to Calling-office Line Telephone Office Telephone Office Line Digital Trunk - DS0 Robbed-bit Signaling is used to transfer signaling information back from called-office to calling-office. Ex. When called-phone answers, or hangs up. 62

Robbed-Bit Signaling in A frame Every 6th frame is robbed of the least significant bit in all channels Bit is used for signaling, not voice. 1 6 12 18 24 24 frames shown Dot is robbed-bit channel 193 bit frame 193 bit frame Channels 1 24 Channels 1 24 1 8 1 8 1 8 63 1 8

Robbed-bit Signaling 56 kbs - Computer to Computer Telephone Office Telephone Office Line Line Digital Trunk - DS0 Robbed-bit Signaling limits the maximum digital bit rate to 56 kbs (DS0=64 kbs). 64

SS7 Signaling - Signaling System 7 SS7 Signaling uses a separate data paths to send call setup information from the calling office to the called office. Out-of-band signaling Big City STP Really Big City SCP database This Town data paths That Town Line Host Office SSP Voice path - Trunk Host Office SSP Line SSP - Signal Service Point - local office STP - Signal Transfer Point - one per regional area SCP - Signal Control Point - database for customer info SS7 is implemented nationally & regionally and is required for advanced features such as caller id, etc. 65

Summary Lines many one-path circuits Trunks fewer two-path circuits Signaling is used for telephone offices to communicate so a telephone call can be set up and taken down. Robbed-bit signaling is an in-band signal system that uses the least significant bit in a DS0 trunk to send signaling between offices. SS7 is an out-of-band signaling system with advanced features. 66

Superframe One frame - 193 bits Superframe 12 frames 1 6 12 Framing bit at beginning of frame before first 8-bit word 193 bit frame 1 24 1 8 1 8 Superframe = 12 frames grouped together 67

One frame (193 bits) Extended Superframe ESF Extended Superframe = 24 frames grouped together 1 6 12 18 24 ESF = 24 frames Framing bits 1 st bit in each frame - Framing bits of 24 frames = virtual 8000 bits/second channel just like a DS0. Framing Channel used to send call setup information without Robbing bits from the bit stream. This allows the entire 64 kbs bandwidth in each DS0 voice channel to send voice information. Also, the Framing Channel sends error checking codes & information about the status of the facility. 68

ISDN - Integrated Subscriber Digital Network Telephone Office 1 cable pair Digital Line all digital connection from telco to phone higher quality voice circuits high speed data lines 69

ISDN BRI - Basic Rate Interface 2 digital voice channels ISDN line card in line bay or channel bank Entire 64 kbs channel used for voice. Network Termination 1 ISDN phone BRI 2B + D = 160 kbs Local 2-wire loop NT1 1 Bearer channel 64 kbs Digital 1-path circuit 1 Bearer channel 64 kbs Telephone office and local loop Demarcation Customer Premise ISDN phone 70

ISDN BRI - Basic Rate Interface One 128 kbs channel ISDN line card in line bay or channel bank 2 Bearer channels BRI 2B + D = 160 kbs Local 2-wire loop NT1 128 kbs Digital 1-path circuit Network Termination 1 Telephone office and local loop demarcation Customer Premise 71

ISDN BRI BRI - Basic Rate Interface all digital circuit 2 B D 16 kbs 64 kbs 64 kbs 160 kbs channel Overhead 16 kbs 2B + D - 2 Bearer channels (2 DS0 S) - 64kb each (voice or data) 1 Data channel - 16kb plus 1 overhead channel for signaling - 16 kb BRI = 2 x 64kb + 16kb + 16kb = 160kb/sec 72

ISDN PRI - Primary Rate Interface format, but channels are - 23B + D = 24 channels 23 Bearer channels 23 DS0 s - 64 kbs each (voice or data) PRI = 23B + D 1 data channel - 64kbit 1 DS0 125 microseconds 8-bit, 64 kbs channels 1.544 Mbs rate 1 24 Framing Bit B B B B B B B B B B B B B B B B B B B B B B B B D 73

Internet Service Provider (ISP) PRI Trunking ISDN BRI Line Internet connection Telephone Office Telephone Office PRI PRI 2B + D PRI, a, uses each entire 64 kbs DS0 channel for information. Signaling information is sent via the Data channel & ESF. Allows for clear channel data transfer ALL 8 bits in each DS0. No Robbed-bit signaling is used. 74

Summary ISDN BRI Basic Rate Interface 2B+D - 2 Bearer channels, 1 Data channel Full 64,000 bits/sec no robbed bits Higher quality, all digital phone lines Used also for data connections. ISDN PRI 23B+D with 23 full 64kbs rate channels Used by Internet Service providers for higher speed connections and ISDN connections. 75

Central Office Layout Outside 2B + D Plant cables Digital switch DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL line ISDN D4 Channel Bank HDSL BRI VF signal M D F termination shelf Span powered (T1) M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 76 OSP fiber cable

Main Distribution Frame C.O. - 2 sided frame Horizontal side Vertical side - cable protectors Horizontal side - line blocks Vertical side 77

Main Distribution Frame - Vertical side - pair protection Protectors - termination of cable pairs - may also have blocks 78

Main Distribution Frame in a typical central office Pair Protection Protectors terminate the outside plant pair provide lightning protection on the pair Blocks terminate the lines from the equipment wired out to a cross connect cabinet Copper pairs in outside plant cable Protector Line equip. jumper Terminal block Equipment cabling Line Equipment Bay 79

Vertical side Cosmic frame 80

Main Distribution Frame cable pair protector (connector) - 100-pair termination of cable pairs - lightning protection; sends lightning surge to the c.o. ground field Protector module (solid state) 81

Main Frame Cable pair protector - jumpers to line circuits of telephone switch. 82

Main Frame Horizontal side Blocks - termination of line circuits 83

Blocks on Main Distribution Frame 84

Blocks Cosmic frame 85

Tipping cables from frame to vault 86

Vault Splice Closures - connects tipping cable to outside plant cable 87

Summary Main Distribution Frame terminates all voice grade connections in a telephone office. Outside Plant cables Line cables Special circuits Pair protection each cable pair is grounded if a lightning surge occurs. 88

Digital switch Central Office Functional Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 89 OSP fiber cable

DSX-1 Cross-connect Connecting circuits between equipment 30-pair high-frequency cabling from equipment jacks Terminates s from equipment Light LED MON OUT IN Bantam patch cord (dual) 30-pair high-frequency cabling from equipment jacks LED MON OUT IN Terminates s from equipment DSX-1 module 5-wire jumper (flipped over) DSX-1 module 90

DSX-1 Bays Terminations for s Cross-connects to other s 91

DSX-1 Bays 92

DSX-1 Bays 5-wire jumpers 93

DSX-1 jumpers what NOT to do 94

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 95 OSP fiber cable

D4 Channel Bank A/D, D/A conversion + TDM 24 Voice Frequency circuits 24 Voice channels 1 24 Low-speed side A/D, D/A D4 channel bank TDM 24 DS0 s 1 1 High-speed side Aggregates many low speed circuits into one high speed circuit for transport 24 low speed circuits - converted to 64kbit/sec DS0 1 high speed side - 1.544 Mbit/sec 96

D4 channel bank 12 channels Common cards for one di-group 12 channels Alcatel (Charles Ind.) - dual di-group - two - 24 channels - common cards in the middle of each di-group (digital group) 97

D4 bank to D4 bank Office A Office B 24 Voice channels 1 D4 channel D4 channel 1 24 Voice channels bank bank 24 24 98

Nortel D4 - dual di-group - two - 24 channels - common cards on right side of shelf 99

Dual Ringing Generators 100

Summary DSX-1 jacks terminating cables, providing cross-connections between circuits. D4 Bank Combines 24 incoming voice channels into 1 output. 24 Low-speed VF A/D, D/A TDM High-speed. 101

Special Circuits Voice Grade: FX - Foreign exchange historically most popular special circuit used for extending dial tone from another office Local office Austin, TX Foreign Dial tone office Washington, DC Line Network Channel Banks 102

Voice Grade: Special Circuits E & M - Ear & Mouth - used for trunk circuits in electromechanical offices. Analog trunks Analog trunks Channel Banks 103

Analog Data: Special Circuits - ETO - Equalized Transmission Only used mainly for sending analog data on/off condition real-time measurements, etc. utility company circuits Channel Banks Data center 104

Digital Data: Special Circuits - Data rates 64 kbs or less (1 DS0 or less) 2.4 kbs, 4.8 kbs, 9.6 kbs, 19.2 kbs, 56 kbs, 64 kbs - Fractional T1 - data rate multiples of 64 kbs 128-384 kbs (2-6 DS0 s) - operates at a rate, but with only the DS0 s used turned on. Typically used with Frame Relay circuits. Channel Banks Digital data Digital data 105

Special Circuits ISDN - Integrated Services Digital Network digital connection from telco to phone 3 DS0's per low speed circuit 3 slots used. ISDN card occupies one slot in channel bank, but the 2nd & 3rd slots are unusable for anything else. 2 Slot-Blocker cards are used to prevent other cards from being placed in the 2 nd & 3 rd slots. 8 ISDN channels MAX per D4 bank or di-group. ISDN circuit Channel bank 3 DS0 s used Channel bank ISDN circuit 1 2 3 4 5 6 7 8 9 10 11 12 Slots in channel bank 106

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 107 OSP fiber cable

ISDN Channel Bank Office A ISDN channel bank Office B ISDN channel bank 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 3 DS0 s per physical slot Only 8 physical slots, not 24 channels Can interface another ISDN bank, D4 or DACS 108

Adtran BR1/10 ISDN dual-channel banks - two di-groups (digital groups) per shelf. 109

Summary Special Circuits: Foreign Exchange dial tone from a different c.o. E & M Ear & Mouth analog trunks ETO Equalized Transmission Only analog data. Digital Data data rates from 2.4 kbs to 64 kbs. ISDN in channel bank uses 3 slots. ISDN Banks have 8 channels per di-group. 110

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 111 OSP fiber cable

DCS Digital Cross-connect System Partial elimination of channel banks Device to access the DS0 s in a bit stream, while keeping the circuits all digital No analog to digital conversion necessary. Facilitates a cost-effective management of special circuits in an office. Higher quality circuits DACS 112

DCS Digital Cross-connect System 24 DS0 s each DACS DS0 cross-connects 113

Why have a DCS? Before DCS: Back-to-Back D4 s VF circuits VF circuits D4 Channel Bank Jumpers D4 Channel Bank D4 D4 Channel Bank Channel Bank D4 D4 Channel Channel Bank Bank Main Distribution Frame 114

DCS - 1/0 input / DS0 cross-connect Back-to-Back D4 elimination Port cards DACS 1/0 DS0 cross-connects in matrix DS0 cross connects in 1/0 DACS D4 Channel Bank.... D4 bank for local circuits. Permanently connected virtual cross-connected DS0 circuits. 115

Digital Cross-connect System Unit shelves & Matrix 28 s Unit Shelves Matrix Unit Shelves 28 s 28 s 28 s 28 s 28 s DS0 cross-connects in matrix input / DS0 cross-connect Inter-shelf bus 28 s 116

DSC - ALCATEL DEXCS Bay layout Fuse Panel Filler Panel Admin Shelf Disk Drive Matrix Shelf Fuse Panel Fuse Panel Unit Shelf Unit Shelf Unit Shelf Fuse Panel Fuse Panel Unit Shelf Unit Shelf Unit Shelf Unit Bay Expansions to 5,376 s Unit Shelf Unit Shelf Admin and/or Matrix Bay Unit Bay Unit Bay Dual, on-line matrices and dual data paths for full circuit protection Fully distributed A and B power feeds Dual power supply architecture Single per port card Distributed processing 117

Alcatel Unit Bay 1 per port card 28 ports per unit shelf 28 ports per unit shelf 28 ports per unit shelf 28 ports per unit shelf 112 ports per bay 118

Alcatel DEXCS 1/0 Bay lineup Unit bays Matrix bay Admin bay 119

Alcatel DEXCS Unit Shelf 28 Ports per shelf Unit cards ( 28 1- cards ) Power Supply card Controller cards Power Supply card 120

Alcatel Narrowband DEXCS sizes - matrix Size CS1S - 84 's - small CS1-336 's - medium CS1L - 1544 's - large Fuse Panel Filler Panel Admin Shelf Disk Drive Matrix Shelf CS1VL - 5376 's - very large 121

Digital Cross-connect Systems Functional types Generic terms Narrowband - 1 / 0 input, DS0 cross-connect Wideband - 3 / 1 DS3 & input, cross-connect Broadband - 3 / 3 / fiber DS3 & fiber optic input, DS3 cross-connect 122

Summary 1/0 DCS input, DS0 cross-connect DCS accesses all DS0 s in a bit stream, while keeping the circuits digital; no A/D conversion reduces the need for back-to-back channel banks for through circuits. Saves on equipment quantity and cost, keeps quality of signal high. Easier to add, delete, & manage circuits. 123

Central Office Concepts Overview Part Two T1 Span lines, HDSL M13 Multiplexer Introduction to Fiber Systems Fiber Cable Termination LGX Broadband DCS Digital Loop Carrier ADSL Timing - BITS Clock Power - AC/DC, Batteries, Generator Grounding - protection from lightning, etc. 124

Digital switch Central Office Layout DCS DSX-1 DSX-1 DSX-1 HDSL line ISDN D4 Channel Bank termination shelf 2B + D BRI VF signal HDSL Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 125 OSP fiber cable

Hi-Cap High Capacity Line to Customer Frame Framing bit Telephone Office DS0 s 1 2 3 24 193 bits/frame Business or Industry Various services can be carried on a hi-cap circuit: PBX trunks (voice), Frame Relay, ATM, ISDN PRI, video, etc. Hi-caps can connect directly to local telco network or pass through to another carrier. 126

Max bit rate = 1.544 Mbs Max frequency = 772 khz + 5 Volts 0 Volts - 5 Volts versus T1 - low voltage levels, typically 5-12 volts. Limitation of 400 ft in an office. +135 Volts T1 - has added DC power component used to power line repeaters. +130 Volts +125 Volts 0 Volts DC power component added 127

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 128 OSP fiber cable

Line Termination Shelf (span shelf) D S X 1 Two 12-pair Shielded Cables Wired to DSX-1 jacks C.O. repeater cards 12-slot shelf Two 12-pair Shielded Cables Wired to block On MDF to access cable pairs 129 To cable pairs

T1 Repeater Housing Telephone pole Aerial or Buried Cable Local Cable or Toll Cable (T-Screen) 12 - Position 25 - Position 50 - Position Housings From previous repeater housing To next repeater housing 130

Span line repeater housing regeneration of signal Pulse degenerates into: Repeater makes a new pulse: Line repeater card From previous repeater housing To next repeater housing 131

New Pulse Generation symbols One pair in and out Side 1 Side 2 Repeater makes a new pulse in each direction 132

Repeater Housing Symbol Side 1 Side 2 133

T1 Repeatered Span Line Central Office A Line Termination Shelf C.O. repeater Central Office B Line Termination Shelf Repeater Housings Line Repeater, 12, 25, 50 slots Outside plant copper cable 134

T1 Span Line - Schematic in DC power component added to signal to power repeater housings - see slide vs. T1 Office A T1 signal (DC powered ) Spacing Between Housings - 3000-5000 feet Office B out out Line termination shelf C.O. Repeater T1 Repeaters Typically, no new T1 span lines are placed, except in rural areas. Line termination shelf 135 in

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 136 OSP fiber cable

HDSL High-bit-rate Digital Subscriber Line Delivers s to remotes, s for customer high-caps WITHOUT a repeater up to 12,000 feet. Central Office HDSL No repeater housings Remote / Customer Premise HDSL Up to 12,000 feet 137

HDSL 00 01 2B1Q - 2 binary, 1 Quaternary Two Binary digits per pulse 4 Pulse levels cuts line frequency in half from T1 HDSL=384 khz; T1=772 khz Distances up to 12,000 without a repeater. 10 11 138

139 HDSL shelf & wiring 12-pair high-frequency cabling to DSX-1 jacks 12-pair high-frequency cabling to main distribution frame C N T R L H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H T U R H D S L

HDSL shelf D S X 1 Two 12-pair Shielded Cables 13-slot shelf Two 12-pair Shielded Cables MDF Block To cable pairs Wired to DSX-1 jacks HTU-C cards HDSL controller card Wired to block on MDF to access cable pairs 140

Central Office HDSL HTU-C & HTU-R Customer Premise DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 HTU-C 2-wire circuit 12 DS0 s HTU-R 2-wire circuit 12 DS0 s DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 HTU-C - HDSL Terminating Unit - Central Office HTU-R - HDSL Terminating Unit - Remote Up to 12,000 feet 141

HDSL Repeater doubles the distance HTU-C HDSL Repeater HTU-R 2-wire circuit 12 DS0 s 2-wire circuit 12 DS0 s 2-wire circuit 12 DS0 s 2-wire circuit 12 DS0 s Central Office 12,000 feet 12,000 feet Customer Premise Two HDSL repeaters may be used to go 36,000 feet 142

Fractional T1 (Fractional ) rate, but with only a portion of the 24 DS0 s carrying traffic - can be delivered via a T1 span line or HDSL customer wanting MORE than ONE 64Kbps channel typically 2-6 DS0's - rate - 128kbps to 384kpbs Can be provisioned on one pair 6 DS0 s shown 24 6 1 Framing bit (1 bit only) 8 7 6 5 4 3 2 1 24 8-bit words +1framing bit = 193 bits 143

Central Office High-speed side 4-wire circuit Fractional T1 over HDSL D4 bank Fractional (6-DS0) 2-wire circuit LC 6 DS0 s in D4 bank 1 Low-speed side MDF 12 HTU-C 2-wire circuit, 2-6 DS0 s, 12 max Only one pair required Up to 12,000 feet Customer Premise 1 6 12 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 HTU-R Fractional T1 with 6 DS0 s carrying traffic 6 1 Customer s Equipment 24 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 24 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 DS0 1 144

Summary Hi-cap to customer T1 span line transports s on copper cable facilities from one office to another; uses T1 repeater housings 3000-5000 feet apart. HDSL transports s on copper cable facilities up to 12,000 feet without a repeater housing. 145

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 146 OSP fiber cable

DSX-3 Cross-Connect - connecting DS3 circuits between equipment coaxial cabling from fiber optic terminal Rear MON Light Front Front MON Rear coaxial cabling From M13 mux DS3 IN OUT I-X O-X jacks DSX-3 module Patch cords jacks IN OUT I-X O-X DSX-3 module DS3 Cables flipped over cross-connect cables (backside of modules) 147

DSX-3 Bay front 148

DSX-3 Lineup 149

DSX-3 Bay- Rear View - equipment termination - cross-connect cables 150

Coaxial Terminations 151

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 152 OSP fiber cable

M13 Asynchronous Multiplexer 28 's multiplex up to 1 DS3 1 to DSX-1 jacks 28...... M13 Multiplexer DS3 to DSX-3 jacks typically use Nortel DMT-300 mux or Telco Systems RC-28D 153

Nortel DMT-300 M13 multiplexer 4 drawers per shelf 30-pair High-frequency Cabling for 28 terminations coaxial cables for DS3 terminations Multiplexer (mux) drawer empty slot 154

Telco 828 M13 multiplexer 155

NEC RC-28D M13 Multiplexer 156

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 157 OSP fiber cable

Fiber System - Async Fundamental structure DS3 working D S X 3.... DS3 Fiber Optic Terminal protection Tx Rx Tx Rx 158

Fiber optic system - interoffice components Office A Point-to-Point configuration Office B D S X 3 DS3 s Fiber Optic Terminal FOT Inside plant mic cable L G X Outside plant fiber cable L G X Fiber Optic Terminal FOT DS3 s Fiber termination panel Fiber optic 159 splice closure D S X 3

Basic Fiber Optic Terminal Simplified block diagram DS3 #1 To DSX-3 panels 45 Mb/s DS3 #2 Tx or In DS3 #3 Rx or Out Low-speed side, or Equipment side D S 3 D S 3 D S 3 M U X 135 Mb/s D E M U X X C V R X C V R 3-DS3 Fiber Optic Terminal To outside plant fiber facilities working Light 1300 nm wavelength protection High-speed side, or Facility side 160

FD-565 Fiber Optic Terminal Power supplies Fiber jumper slack storage Controller card Coaxial termination Working side Optics cards (Tx, Rx, Mux, Demux) Protection side Optics cards DS3 interface cards Transmit card Receive card 161

Multiplexing Hierarchy & wiring DS0 channel 1 DS0 channel 24 64 Kbs D4 Channel bank 1.544 Mbs #1 M13 mux 45.736 Mbs DS3 Fiber Optic Terminal #28 FOT 25-pair 24-gauge voice frequency cable 30-pair 24-gauge shielded cable Coaxial cable Fibers to next office 162

Test Equipment, DS3, SONET T-Berd Acterna Products - formerly TTC 163

Mux, DSX-3, & F.O.T. connections coaxial cross-connect Highfrequency cabling M13 MUX DS3 cords coaxial cable DSX-3 PANEL DSX-3 PANEL DS3... DS3 coaxial cable Fiber Optic Terminal working protection To fiber termination panel Tx Rx Tx Rx 164

Summary DSX-3 jacks - terminating DS3 cables, providing cross-connections between DS3 circuits. Connects to M13 muxes & FOT s. M13 Multiplexer TDM device combining 28 s into one DS3. Fiber Optic Terminal TDM device combining lower speed DS3 (and ) circuits together into a high speed circuit. This high speed circuit is converted into light pulses and connected to a fiber cable. 165

SONET Synchronous Optical NETwork SONET is a standard for synchronous data transmission on fiber optic equipment. STS-1 Synchronous Transport Signal rate 1. - fundamental bit rate within SONET hierarchy. SONET rate = 51.840 Mbs. When transmitted via light, called Optical Carrier rate 1, or OC-1. STS-1 typically is a DS3 signal within a SONET frame. SONET Frame Header 28 27 26 5 4 3 2 1 DS3 166

SONET Frame Synchronous Transport Signal Rate - 1 Optical Carrier - Rate 1 Transport Overhead STS-1 electrical, OC-1 - optical 90 Columns 9 Rows 8-bit word Payload 87 Columns 8-bit word Frame Rate=9 Rows X 90 Columns X 8 bits/sec X 8000 frames/sec = 51.84 Mbs Payload = 50.112 Mbs, Transport Overhead = 1.728 Mbs 167

SONET Advantages: Mix and match fiber vendors on same span. Since the SONET bit streams are byteinterleaved and timed from a common, stable clock source, the individual lowerrate bit streams can be accessed without demultiplexing the entire bit stream. Vendor A Vendor B....... DS3 SONET Fiber Optic System SONET Fiber Optic System....... DS3... 168

SONET Hierarchy & Rates # DS3's SONET OPTICAL Rate Capacity - 's 1 STS-1 OC-1 51.84 Mbs 28 's 3 STS-3 OC-3 155 Mbs 84 's 12 STS-12 OC-12 622 Mbs 336 's 48 STS-48 OC-48 2488 Mbs - 2.4 Gbs 1344 's 192 STS-192 OC-192 9953 Mbs - 9.9 Gbs 5376 's..... DS3 SONET Fiber Optic System 169

Lucent DDM-2000 Transceiver cards OC-3 shelf Processor cards Timing Cards Interface cards Group A 28 s Group B - empty Group C - empty Drop down door 170

SONET Fiber Optic System Synchronous Optical NETwork OC12 Transceiver cards Operational Controller OPC Timing cards DS3 or Interface cards Fan shelf Processor card 171

Fujitsu FLM-150 Fiber Shelf 172

173 12 STS-1 s maximum available around the ring. SONET Rings UPSR - Uni-directional Path Switched Ring B 12 STS-1 s OC-12 UPSR Ring Number of available STS-1 s = rated capacity of system (N) DS3 s DS3 s DS3 s Example: A-B - Ch.1 working B-C-A - Ch.1 protection X where DS3 interfaces the ring. C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G B C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G A C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G C

174 SONET Rings BLSR Bi-directional Line Switched Ring Number of available STS-1 s = N/2 * number of nodes Each segment is has ½ working STS-1 s and ½ protection STS-1 s A B C ½ STS-1 s working & ½ STS-1 s protection ½ STS-1 s working, ½ STS-1 s protection ½ STS-1 s working, ½ STS-1 s protection C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G B C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G A C O N T R O L P O W E R P O W E R O C - 12 X C V R O C - 12 X C V R P R O T. M A P P E R S W I T C H E R M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S M A P P E R 14 D S- 1' S T I M I N G C DS3 s DS3 s DS3 s 6 STS-1 s available in each segment. OC-12 BLSR Ring

Summary SONET standard format for fiber optic equipment. Accesses bits in the bit stream without de-multiplexing the entire bit stream. Allows concatenation of signals together for higher speeds. Equipment must be synchronized or timed together. 175

Fiber Cable Termination OSP cable - closure - fiber panel Fiber closure fiber connector panel Outside Plant fiber cable Inside Plant fiber cable (mic cable) 176

LGX Light Guide Cross-Connect Fiber connectors 6-pack Bulkhead connector - mates to fiber optic connector Fiber optic connector Pigtail (or jumper) 177

Fiber optic connectors Bulkhead connector in termination shelf Fiber optic connector Fiber optic pigtail facility side Mated together in fiber termination shelf Fiber optic jumper equipment side 178

Fiber Optical connectors ST SC FC Biconic Most commonly used in telephony Used in video applications Older type, not being placed in new systems 179

Fiber Termination Bays - Lucent LGX Light Guide Cross-connect also called, OSX - Optical Signal Cross-connect Facility-side bay & equipment-side bay 180

Fiber Termination Bay - ADC Fiber termination panel jumpers slide out to side 181

Fiber termination shelves Fiber pigtail (72 in bundle) Connectors (72 per shelf) Fiber jumpers Fiber termination shelf Designation strip 182

OCEF Optical Cable Entrance Facility MIC cable from LGX bay 183

Fiber Jumper Inter-connect Fiber closure LGX panel Outside Plant Fiber MIC cable - terminates on back of LGX panel Fiber Jumper - connects to front of LGX panel Fiber Optic Terminal 184

Fiber Jumper Connections Inter-connect Fiber optic connectors Fiber closure LGX panel top view Equipment Jumpers (4) MIC cable 12-, 24-, 72-fiber, etc. Fiber Optic Terminal 185

Fiber Jumper cross-connect Fiber closure LGX panel facility side LGX panel equipment side Fiber Optic Terminal mic cable - terminates on back of LGX panel Fiber X-C Jumper - terminates on front Fiber equipment Jumper - terminates on rear 186

Fiber Jumper Connections Cross-connect LGX panel facility-side LGX panel equipment-side Fiber closure MIC cable 12-, 24-, 72-fiber, etc. ST connectors Cross-connect Jumpers (4) Equipment Jumpers (4) Fiber Optic Terminal 187

Summary LGX fiber cable & jumper termination; allows for fiber cable management. MIC cable is fire retardant ST & SC connectors are the most commonly used in telephony. Inter-connect & cross-connect are both used. 188

Tracing an FX circuit through an office Summary of circuits, signals & equipment FX circuit D4 channel bank DSX-1 DSX-1 M13 Multiplexer DS3 D S X 3 D S X 3 DS3 Fiber Optic Terminal DSX-1 DSX-1 work prot MDF DS0 matrix Fiber jumpers LGX LGX DACS Outside Plant fiber cable Over network to foreign exchange for dial tone 189

Wave Division Multiplexing WDM WDM is used to place multiple wavelengths of light on a single fiber. Fiber Optic Tx Terminal #1 WDM Device WDM Device Fiber Optic Rx Terminal #1 Office A Office B Fiber Optic Tx Terminal #2 + Fiber Optic RxTerminal #2 190

Wave Division Multiplexing Wavelengths of Light Nanometers nm Wave length(s) Lambda - λ Fiber optic lasers traditionally operated at 1310 nm, 1550 nm. Dense Wave Division Multiplexing uses finer increments of wavelengths 0.1 nanometers. DWDM uses wavelengths such as 1557.1, 1557.2, 1557.3, 1557.4, and higher. 191

Basic Wave Division Multiplexing Both 1310 nm and 1550 nm light signals are on same fiber in one direction. Office A Fiber Optic Tx Terminal #1 Rx Only the Working side is displayed. WDM Device WDM Device Office B Tx Fiber Optic Rx Terminal #1 1310 nm λ 1 λ 1 1310 nm WDM - passive devices, no power required 1550 nm λ 2 Fiber Optic Tx Terminal #2Rx Fiber optic cable Between telephone offices λ 2 Tx Rx 1550 nm Fiber Optic Terminal #2 Requires ONLY four fibers, NOT eight fibers. Not shown are the fiber termination panels, etc. 192

DWDM Four wave length system Office A Requires only four fibers, not sixteen fibers. Office B F.O.T.#1 1557.1 Tx F.O.T.#2 1557.2 Tx F.O.T.#3 1557.3 Tx F.O.T.#4 1557.4 Tx Rx Rx Rx Rx F.O.T.#1 1557.1 F.O.T.#2 1557.2 F.O.T.#3 1557.3 F.O.T.#4 1557.4 F.O.T.#1 1557.1 Rx F.O.T.#2 1557.2 Rx F.O.T.#3 1557.3 Rx 4-input WDM Device 4-input WDM Device F.O.T.#3 1557.3 F.O.T.#4 1557.4 Rx Tx F.O.T.#4 1557.4 Tx Tx Tx F.O.T.#1 1557.1 F.O.T.#2 1557.2 Transmitter and receivers must be matched properly. Only the Working side is displayed. 193

F.O.T. Transmitters DWDM 8 wavelength system 1557.1 1557.2 1557.3 1557.4 1557.5 1557.6 1557.7 1557.8 Office A 8-input WDM device 8-input WDM device Office B F.O.T. Receivers 1557.1 1557.2 1557.3 1557.4 1557.5 1557.6 1557.7 1557.8 Requires only four fibers, not thirty-two fibers. Only one direction of the working sides shown. 194

Summary Wave Division Multiplexing is used to add another fiber optic system to the same set of fibers, but with optic cards with different wavelengths. DWDM adds many fiber systems to the same set of fibers, with optic cards only 0.1 nm apart in wavelength. 195

Wideband DCS DS3, SONET fiber input, cross-connect Verizon approved Tellabs Titan 5500 DS3 DS3 DCS 3/1 - Grooming circuits from one port to another. - Reduces back-to-back equipment. Port cards DS3 DS3 DS3 DS3 cross-connects in matrix cross connects in 3/1 DCS SONET Fiber optic interface OC-1, OC-3, OC-12 196

Tellabs Titan 5500 SONET 3/1 DCS 197

Titan 5500 unit shelf DS3 input 198

SONET Broadband DCS DS3, SONET fiber input, DS3 cross-connect Grooming DS3 circuits from one port to another. DCS 3/3 Port cards DS3 DS3 DS3 DS3 cross-connects in matrix SONET Fiber optic interface OC-1, OC-3, OC-12 DS3 cross connects in 3/3 DCS 199

Summary Wideband DACS DS3/fiber input, crossconnect; management of circuits. Reduces the need for M13 multiplexers, DSX-1 jack panels, etc. Broadband DACS DS3/fiber input, DS3 cross-connect; management of DS3 circuits. Reduces the need for fiber optic terminals; allows direct interface of fiber optics. Reduces the need for DSX-3 jack panels. 200

Microwave Radio Point-to-Point Radio Transmission 201

Microwave Radio Point-to-Point - & DS3 circuits 2 11 GigaHertz Microwave carrier frequencies Parabolic Dish Antenna Waveguide Telephone Office Telephone Office Tower structure 202

Microwave Radio Waveguide Waveguide DS3 Microwave Parabolic Dish Antenna Radio DS3 Terminal DSX-3 Panel coaxial cable 3-DS3 maximum per radio Tower structure 203

Microwave Radio Equipment Telephone Office Wave guide Radio/Antenna Interface - Rigid Waveguide Ports MW Radio Equipment Tower structure or DS3 Inputs 204

Microwave Radio Frequencies & Distances 2 GHz now used for PCS. Existing systems - grandfathered 6 GHz 11 to 30 miles 11 GHz 3 to 15 miles 18 GHz 0 to 5 miles 38 GHz across the street Typically, transmit power is only one Watt. Microwave dishes are from 2 15 feet in diameter. The larger the dish, the higher the gain, hence greater distance is achieved. 205

Microwave Radio Passive Reflector Telephone Office Reflectors are used to bounce microwave beam over or around an obstruction. Telephone Office 206

Summary Microwave Radio used to transport telephony signals in lieu of fiber cable; over mountains, bodies of water, etc. Both and DS3 circuits are transported 207

Digital Loop Carrier Existing copper plant Telephone Office Distribution cables 600-pair Feeder cable 450 homes 500-pair feeder cable 100-pair feeder cable Distribution cables 75 homes 208

Digital Loop Carrier DLC added in growing subdivision Telephone Office Distribution cables 600-pair Feeder cable 450 homes 500-pair feeder cable 100-pair feeder cable DLC Distribution cables 75 homes 300 new homes 209

Digital Loop Carrier DLC distribution cable & span cable added Telephone Office Distribution cables 600-pair Feeder cable 450 homes 500-pair feeder cable Existing distribution cable Distribution cables 100-pair feeder cable New T1 ( or HDSL) span cable DLC 75 homes 300 new homes New DLC distribution cable 210

Digital Loop Carrier DLC is cutover; old feeder cable is free to be reused Telephone Office Distribution cables 600-pair Feeder cable 450 homes 500-pair feeder cable Existing 100-pair feeder cable can be reused for other customers New distribution cables for another subdivision Distribution cables 100-pair feeder cable New T1 ( or HDSL) span cable DLC 75 homes 300 new homes New DLC distribution cable 211

NGDLC Next Generation Digital Loop Carrier To provide telephone services to areas where it would be economically unfeasible to place copper cable. Fiber or copper s to central office POTS Special Circuits - ISDN, FX, etc. Hi-caps ADSL DLC cabinet Concrete pad Cross-connect cabinet AFC AccessMax (formerly UMC-1000A), Alcatel Litespan, Zhone (formerly Nortel) AccessNode, Lucent SLC-96, SLC-5, SLC-2000 Marconi DISC*S (Reltec), and others. 212

Digital Loop Carrier cabinet site 672 lines maximum Digital Loop Carrier cabinet Generator Cross connect cabinet AC Power cabinet Outside plant cable 213

Walk-in Cabinet 672 to 2688+ lines 214

Walk-in Cabinet Digital Loop Carrier equipment (lines) directly cabled to protectors. Protectors Cabled to external cross-connect cabinet no blocks, no jumpers required in DLC cabinet. DLC bays Protectors 215

DLC Digital Loop Carrier Universal arrangement Central office / remote COT - Central Office Terminal Line bay MDF Central Office DLC Fiber optics or copper s DLC cabinet 672 lines 672 lines Jumpers Cross-connect cabinet 240 lines 216

DLC Digital Loop Carrier Direct interface into switch Host central office port bay Central Office DLC DLC cabinet 672 lines interfaces 4-6 connections no lines Fiber optics DLC cabinet Cross-connect cabinet 4-6 connections 672 lines Line termination shelf Copper span lines 217

Main Distribution Frame in DLC s & walk-in cabinets Equipment Protection Protectors terminate the lines from the equipment provide lightning protection on the equipment Blocks terminate the outside plant pair also used in walk-in cabinets Cable pair Terminal block Line equip. jumper Protector Equipment cabling DLC line equipment 218

Digital Loop Carrier DLC is telephone line equipment placed in an area where it is more cost effective than placing copper facilities to the area. DLC protectors 800-pair Equipment Side Cross-Connect cabinet 1600-pair Field side jumpers terminals Fiber termination Fiber cable panel to central office Inter-cabinet cabling Ground rods for ground field Outside Plant distribution 219 cable

ADSL Asymmetrical Digital Subscriber Line Telephone Office ADSL Basic phone circuit And Digital Subscriber Line for High Speed Internet Service On One cable pair 220

Asymmetrical Digital Subscriber Line Signal level ADSL Cable Pair Spectrum High speed internet with phone both working at same time. POTS ADSL Upstream bandwidth ADSL Downstream bandwidth Frequency 4kHz 20 khz 140 KHz 1.1 MHz Signal versus Frequency 221

Basic phone circuit before ADSL POTS Line Bay LC Telephone Office Jumper Regular NID Line cabling Line Block Protector Cable Pair LC-line card Main Distribution Frame 222

Basic phone circuit - with ADSL POTS Line Bay LC Telephone Office Line Block Protector Splitter NID ATU-R to Frame Relay switch ADSL Line cabling A T U C Fujitsu Speedport ADSL Jumpers Splitter Block Main Distribution Frame Cable Pair Ethernet connection xlc=xdsl line card 223

Fujitsu ADSL shelf MDF-mounted splitter block - passive electronics 48 circuits per shelf. 16 circuits per splitter block. 3 splitter blocks required per shelf. Jumper to line circuit, and jumper to cable pair Newer installations use rack-mounted splitter 224

ADSL Service Offerings Bronze CIR=10 kbs 256 kbs downstream / 64 kbs upstream Silver CIR= 32 kbs 384 kbs downstream / 384 kbs upstream Gold CIR = 64 kbs 768 kbs downstream / 768 kbs upstream Platinum CIR = 192 kbs 1.5 Mbs downstream / 768 kbs upstream Platinum Plus - Multi-User CIR=384 kbs 1.5 Mbs downstream / 768 kbs upstream CIR = Committed Information Rate 225

Carriers used by ADSL to send high-speed digital bit stream Signal level QAM Quadrature Amplitude Modulation. 2-8 bits per carrier. Bit rate 64 Kbs-768 Kbs Upstream Bit rate 256 Kbs-1.5 Mbs Downstream 3 khz spacing between carriers POTS frequency 0 khz 4kHz 20 khz 140 KHz 1.1 MHz ADSL carriers or channels 227 maximum carriers Weak frequency in cable pair 226

Test Board in C.O. 6 Line Protector ADSL Components at Customer Premise CAT 5 Patch Cable between RJ48 and Modem RADSL Modem RJ48 ADSL Data RJ11 Voice Power Supply CAT 5 Patch Cable between Modem and NIC card in PC Homerun RJ48 if Customer has second line. Network Interface Card 227

G.Lite Universal ADSL Universal ADSL or G.Lite Lower bit-rate & lower frequency ADSL service 1.5 Mbs downstream / 384 kbs upstream Splitter-less NID Works through special line card in existing line bay. Cable pair Regular NID Microfilter G.Lite Upstream Downstream POTS 0 khz 4kHz 20 khz 140 KHz 550 KHz 1.1 MHz 228

G.Lite POTS Line Bay xlc 1-pair Universal ADSL 2-wire jumper Regular NID Microfilter D-BIC Line cabling Line Block Protector - Splitter-less, lower bit-rate ADSL Cable Pair G.Lite to Frame Relay switch - 1.5 Mbs downstream - 384 kbs upstream - Standard protocol - works with Modification to Line bay; D-BIC Data-Bus Interface Card any vendor s ADSL equipment - Small modification to line bay Main Distribution Frame xlc=xdsl line card 229

Summary ADSL POTS & high speed data over same cable pair. Keeps Internet traffic off of the Public Switched Telephone Network (PSTN). G.Lite lower speed & splitter-less version of ADSL. 230

TIMING - What is it? Everybody is marching to the same 'beat' BITS - Building Integrated Timing Supply Stable timing source for digital networks allows equipment to synchronize or 'sync up to one reliable timing source so digital circuits are timed together. 231

TIMING - Why is it? Required for prevention of Binary Digit Slips a slip is loss of a block of bits due to frequency shift, phase shift, etc. between networks. causes outages, loss of data, audible clicking on line, facsimile distortions Bit Slip Original Signal 232

TIMING - For what equipment? Purely analog circuits DO NOT require timing. Timing required for: D4 channel banks only for digital circuits SONET fiber systems DACS Digital switch 233

TIMING - How? BITS Clock Building Integrated Timing Supply Clock accurate & stable clock oscillator obtains timing from the GPS - Global Positioning System GPS distributes a timing reference to non-gps sites 234

GPS & BITS Clock GPS satellites gathers timing references from multiple satellites power cable to roof mounted receiver Stratum 2 Clock GPS receiver on roof Coaxial or fiber cable from roof to timing shelf 235

GPS Antenna 236

3 clock levels of timing - Stratum Levels Telephone Office GPS Telephone Office GPS Stratum 1 Stratum 1 Stratum 2 Stratum 2 Stratum 3 Stratum 3 Stratum 3 Telephone Office Telephone Office Telephone Office 237

TIMING - Stratum levels Stratum 1 Clock - directly from GPS receiver typically put at host offices with Stratum 2 stability infinite continuously connected to GPS Stratum 2 Clock - stability - 28 days w/out external input Stratum 3 Clock - stability - 5 days w/out external input typically put at main wire centers other than hosts Stratum 4 Clock - stability - less than 24 hours typically for clocks put on fiber optic cards 238

BITS Clock/Timing Distribution Shelf & GPS Antenna control shelf 239

BITS GPS Antenna Power cable to roof mounted receiver Stratum 2 Clock Coaxial cable or fiber cable from roof to timing shelf Timing Outputs TOCA output or composite clock. DS0 outputs to channel banks, ISDN banks, DLC s. TOCA Output TOTA Output TOTA output. outputs to digital switch, 1/0 DACS, 3/1 DACS, Broadband DACS, SONET fiber optic terminals, etc. 240

Summary Timing keeping all digital circuits and equipment synchronized together to prevent loss of information. GPS Global Positioning System an accurate timing source sent from satellites to a roof mounted receiver.\ BITS Building Integrated Timing Supply supplies accurate timing signals for all equipment in a telephone office. 241

c.o. ground bus AC AC + - Power Common bus for (+) & ( -) - + -48V -48V DC DC meters Fuses - + shunt To C.O. equipment -48V Rectifiers AC to DC Input power: - 120/240 Volts-AC - 208 or 440 Volts-AC 3-phase Power Board Batteries Output power: large office - 600-10,000+ Amps @ -48 VDC small office - 100-600 Amps @ -48 VDC 242

Main Power Board 4 main fuses (600 Amp) - for feeding secondary power boards Distribution: 32 A fuses (30 Amp) 32 B fuses (30 Amp) - for feeding fuse panels in equipment bays. 243

POWER Main Power Board Voltage Shunt Current measures voltage & current used by office Shunt - measures current - ammeter provides main fuses to power secondary distribution boards may provide distribution fuses for transmission racks (remote) provides a 'battery return' bus for battery grounds Fuses 244

Shunt used to measure office current individual plates Shunt - Measures current by measuring voltage. - provides protection for power plant - plates heat up & fall out or burn up Measured Current = Voltage drop across shunt Resistance plates - known, accurate 245

POWER Secondary Power Distribution Boards Switching PDC - Power Distribution Center located in switching lineup Transmission - BDFB - Battery Distribution Fuse Board located in transmission equipment area Voltage Current 246

Nortel Switching PDC Power Distribution Center for digital switch 247

POWER Transmission Distribution Power Board B-side A-side shunt Voltage shunt Current provides secondary power distribution to transmission racks may be fuses or breakers A & B sides - 2 Shunts, 2 voltmeters, 2 ammeters powers A & B battery & ground to fuse panels with 2 power inputs distribution fuses typically 10 to 30 Amp requires two 600-Amp fuses from Main Power Board for diversity protection Fuses or breakers 248

Main Power Board feeding Transmission Power Board Main Power Board Transmission Power Board shunt shunt shunt Voltage Current Voltage Current A side -48V B side To Transmission Racks to Power fuse panels. 600 Amp fuses BDFB 30-70 Amp fuses / breakers 249

Power Distribution Dual power feeds with ground Battery plant Ground Bar Ground cable BDFB Ground Bar Ground leads Fuse panel shunt Shunt Shunt Shunt Voltage Current Voltage Current A side Telephone -48V Equipment B side Equipment Main Power Board BDFB Rack 250

Transmission Distribution Power cables Feeding power Board, and Powering other Equipment. Power Board A side Distribution Meter Panel for A & B sides 30 Amp breakers B side Distribution 251

Secondary Distribution panel Shunt panel Meter panel Main Distribution panel Secondary Distribution panel Remote building Power Board with Rectifiers Two Rectifiers, 100-Amp each - Load not to exceed 100 Amps (Maximum load +1 rectifier) 252

Batteries C.O. ground bus Common bus for (+) & ( -) AC + - - + -48V -48V - + Shunt To C.O. equipment Voltage Current DC DC -48V AC Rectifier AC to DC Batteries 3-hour backup with Generator 8-hour backup without Generator Power Board Main or Distribution 253

Batteries 24 Cells -48 Volts nominal -52 Volts Charge voltage Wet Cell - lead calcium 20-25 year life 254

Batteries - Sealed Dry cells - Valve Regulated - GNB Absolyte has Absorbent glass mat. - 20 year life 255

Backup Generator provides electrical power to run the office in event of A/C power failure - typically 7.5 kw to 60 kw units larger sizes for main central offices 250kW to 750kW+ runs on propane (older installations) or diesel fuel (newer installations. Shown is a 365 kw diesel Generator. 256

Commercial AC Power AC Transfer Switch Normal Automatic Transfer Switch AC Load Backup Generator Emergency To: rectifiers air conditioning lights 257

Grounding Keep People & Equipment Safe from Lightning 4 Grounding Elements: Producers Absorbers Isolated Ground Zone - IGZ Non-Isolated Ground Zone - Non-IGZ 258

Grounding Producers anything that allows lightning gets into a telephone office. sheath of cables entering office firing point of protector modules radio towers MDF protectors Grounding points connected to ground bar Outside plant Copper cable 259

Grounding Absorbers anything that absorbs a lightning surge. ground field around office - 5 ohm ground desired building structure / metal water pipes Telephone Office Ground field/ring 8-foot deep ground rods buried 8-feet apart 260

Grounding Master Ground Bar MGB Producer Absorber Non-IGZ IGZ 261

Master Ground Bar - MGB Producers Absorbers Non-IGZ IGZ P.A.N.I. bar 262

Grounding IGZ IGZ - Isolated Ground Zone All cards in equipment bays are isolated from the bay ironwork. Digital switch has a separate IGZ bus bar - Ground Window Bar - GWB GWB connects to IGZ zone on MGB Ground Window Bar - GWB To IGZ (digital switch) MGB 263

Grounding Non-IGZ Non-Isolated Ground Zone Transmission equipment: May not have the cards isolated from the shelves May not have the shelves isolated from the bays Cards i.e. the cards & shelves may be grounded to the ironwork which violates the IGZ concept Fuse panel Transmission Equipment shelf Transmission Equipment Rack 264

Digital switch Central Office Layout DCS 1/0 DSX-1 DSX-1 DSX-1 HDSL ISDN D4 Channel Bank line termination shelf HDSL 2B + D BRI VF signal Span powered (T1) Outside Plant cables M D F M13 Mux DS3 coaxial cable DSX-3 DSX-3 DS3 coaxial cable Fiber Optic System fiber jumpers LGX 265 OSP fiber cable