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ACES ECE RVW / AMPARO BLDG / IPQUINTO

WIRED WIRED COMMUNICATIONCOMMUNICATION

SS

IRINEO P. QUINTOIRINEO P. QUINTO

ECE / REEECE / REE


FUNCTIONS OF THE FUNCTIONS OF THE TELEPHONE SETTELEPHONE SET

• TO CALL THE LOCAL EXCHANGETO CALL THE LOCAL EXCHANGE• TO TRANSMIT THE DESIRED TO TRANSMIT THE DESIRED

SUBSCRIBER’S NUMBERSUBSCRIBER’S NUMBER• TO RECEIVE DIFFERENT TONE TO RECEIVE DIFFERENT TONE

SIGNALSSIGNALS• TO ANNOUNCE INCOMING CALLSTO ANNOUNCE INCOMING CALLS• TO TRANSMIT AND RECEIVE TO TRANSMIT AND RECEIVE

SPEECHSPEECH• TO ORDER THE CLEARING OF TO ORDER THE CLEARING OF

CONNECTIONCONNECTION


PARTS OF A TELEPHONE PARTS OF A TELEPHONE INSTRUMENTINSTRUMENT

• HANDSETHANDSET– CONTAINS THE CONTAINS THE

TRANSMITTER AND TRANSMITTER AND THE RECEIVERTHE RECEIVER

– THE TRANSMITTER THE TRANSMITTER CONVERTS THE CONVERTS THE SOUND INTO SOUND INTO ELECTRICAL SIGNAL. ELECTRICAL SIGNAL. IT IS A CARBON TYPE IT IS A CARBON TYPE MICROPHONE.MICROPHONE.

– THE RECEIVER THE RECEIVER CONVERTS THE CONVERTS THE ELECTRICAL SIGNAL ELECTRICAL SIGNAL INTO SOUND WAVES. INTO SOUND WAVES. IT IS A DYNAMIC TYPE IT IS A DYNAMIC TYPE SPEAKER.SPEAKER.

• RINGER / ALERTERRINGER / ALERTER– USEDTO ANNOUNCE USEDTO ANNOUNCE

INCOMING CALLINCOMING CALL– IT IS A SPEAKER IN IT IS A SPEAKER IN

ELECTRONIC ELECTRONIC TELEPHONE SETTELEPHONE SET

– IT IS MADE-UP OF AN IT IS MADE-UP OF AN ARMATURE AND A ARMATURE AND A GONG IN ANALOG GONG IN ANALOG TYPE ISNTRUMENT TYPE ISNTRUMENT (BELL)(BELL)



• HYBRID / SPEECH HYBRID / SPEECH CIRCUITCIRCUIT– USED MINIMIZE USED MINIMIZE

THE SIDETONETHE SIDETONE– MATCHES THE MATCHES THE

FOUR WIRE (RX & FOUR WIRE (RX & TX) TO THE TWO TX) TO THE TWO OF THE OF THE SUBSRCIBER’S SUBSRCIBER’S LOOPLOOP

• TRANSMISSION TRANSMISSION REGULATION REGULATION CIRCUITCIRCUIT– USED TO SET THE USED TO SET THE

DESIRED SIGNAL DESIRED SIGNAL LEVEL AT THE LEVEL AT THE TELEPHONE TELEPHONE INSTRUMENTINSTRUMENT



• DIAL ASSEMBLYDIAL ASSEMBLY– USED TO USED TO

TRANSMIT THE TRANSMIT THE DESIRED DESIRED SUBSCRIBER’S SUBSCRIBER’S NUMBERNUMBER

– PULSE TYPE OR PULSE TYPE OR TONE TYPE TONE TYPE DIALINGDIALING

1A

DEF 3

ABC2

GHI4

BMNO

6JKL5

PRS7

CWXY

9TUV

8

* D#OPER0

1209

1336

1477

1633

697

770

852

941


FUNCTIONS OF A FUNCTIONS OF A TELEPHONE NUMBERTELEPHONE NUMBER

• IT ROUTES THE CALLIT ROUTES THE CALL• IT ACTIVATES THE NECESSARY IT ACTIVATES THE NECESSARY

APPARATUSES FOR PROPERCALL APPARATUSES FOR PROPERCALL CHARGINGCHARGING

INTERNATIONAL ACCESS CODE

COUNTRY CODE

AREA CODE

TELEPHONE NUMBER

00

1,2 OR 3 DIGITS

1,2 OR 3 DIGITS

63

123

7531496


SUBSCRIBER LOOP SUBSCRIBER LOOP INTERFACE CIRCUIT INTERFACE CIRCUIT

(SLIC)(SLIC)• PERFORMS THE FOLLOWING PERFORMS THE FOLLOWING

BORSCHT FUNCTIONSBORSCHT FUNCTIONS

BORSCHT

BATTERY

RINGING

SUPERVISORYCODING

HYBRID

TESTING

OVERVOLTAGE PROTECTION


SWITCHING SWITCHING TECHNIQUESTECHNIQUES

• MANUAL MANUAL SWITCHINGSWITCHING– USED SWITCH USED SWITCH

BOARDS MAN BY BOARDS MAN BY OPERATORSOPERATORS

• STEP BY STEPSTEP BY STEP– USED STROWGER USED STROWGER

SWITCHSWITCH– CONSISTS OF LINE CONSISTS OF LINE

FINDER, SELECTOR & FINDER, SELECTOR & CONNECTORCONNECTOR

• CROSSBAR CROSSBAR SWITCHINGSWITCHING– USED COMMON USED COMMON

CONTROL CONTROL SWITCHINGSWITCHING

– USED CROSSPOINT USED CROSSPOINT CONNECTIONSCONNECTIONS

– ALLOWS ALTERNATE ALLOWS ALTERNATE ROUTEROUTE

• ELECTRONIC ELECTRONIC SWITCHING SYSTEMSWITCHING SYSTEM– ADDS MORE ADDS MORE

FEATURES IN THE FEATURES IN THE TELEPHONE SYSTEMTELEPHONE SYSTEM


SIGNALING FUNCTIONSSIGNALING FUNCTIONS• RINGING SIGNALRINGING SIGNAL

– USED TO OPERATE A USED TO OPERATE A VISIBLE OR AUDIBLE VISIBLE OR AUDIBLE ALARM TO ALERT THE ALARM TO ALERT THE SUBSCRIBER OF AN SUBSCRIBER OF AN INCOMING CALLINCOMING CALL

• SUPERVISORY SUPERVISORY SIGNALSSIGNALS– USED TO CONVEY USED TO CONVEY

INFORMATION INFORMATION REGARDING THE REGARDING THE SWITCHBOARD SWITCHBOARD CONDITIONS (ON-CONDITIONS (ON-HOOK OR OFF-HOOK)HOOK OR OFF-HOOK)

• ADDRESS SIGNALSADDRESS SIGNALS– CONVEY DIALING OR CONVEY DIALING OR

DIGITAL DIGITAL INFORMATION INFORMATION NECESSARY TO NECESSARY TO ESTABLISH THE ESTABLISH THE DESIRED DESIRED CONNECTIONSCONNECTIONS

• SIGNALING SIGNALING PROVIDES A MEANS PROVIDES A MEANS OF OPERATING AND OF OPERATING AND SUPERVISING A SUPERVISING A TELEPHONE TELEPHONE COMMUNICATIONS COMMUNICATIONS SYSTEMSYSTEM


TYPES OF SIGNALINGTYPES OF SIGNALING• SUBSCRIBER LOOP SUBSCRIBER LOOP

SIGNALINGSIGNALING– WET-DRYWET-DRY– REVERSE BATTERYREVERSE BATTERY– HIGH-LOWHIGH-LOW

• E & M SIGNALING E & M SIGNALING (EAR & MOUTH)(EAR & MOUTH)– USED TWO LEADS TO USED TWO LEADS TO

CONNECT THE CONNECT THE SIGNALING SIGNALING EQUIPMENT TO THE EQUIPMENT TO THE TRUNKTRUNK

• OUT OF BAND OUT OF BAND SIGNALINGSIGNALING– USED ONE OR MORE USED ONE OR MORE

AC TONES THAT LIES AC TONES THAT LIES IN THE PASSBAND OF IN THE PASSBAND OF THE TRANSMISSION THE TRANSMISSION FACILITY BUT FACILITY BUT OUTSIDE THE VOICE OUTSIDE THE VOICE BANDBAND

– 3700 Hz – BELL; 3825 3700 Hz – BELL; 3825 Hz – CCITTHz – CCITT

• IN-BAND SIGNALINGIN-BAND SIGNALING– SIGNALING TONE ARE SIGNALING TONE ARE

TRANSMITTED WITHIN TRANSMITTED WITHIN THE SPEECH BANDTHE SPEECH BAND

– 1600, 2400 OR 2600 Hz 1600, 2400 OR 2600 Hz (TYPICAL)(TYPICAL)


SUBSCRIBER’S LOOP SUBSCRIBER’S LOOP DESIGNDESIGN

(OUTSIDE PLANT)(OUTSIDE PLANT)• ATTENUATION ATTENUATION

LIMIT LIMIT (TRANSMISSION (TRANSMISSION DESIGN CRITERIA)DESIGN CRITERIA)– REFERS TO THE AC REFERS TO THE AC

LOOP LOSS AT THE LOOP LOSS AT THE REFERENCE REFERENCE FREQUENCYFREQUENCY

– 1000 Hz – 1000 Hz – CCITT/NORTH CCITT/NORTH AMERICANAMERICAN

– 800 Hz - EUROPE800 Hz - EUROPE

• SIGNALING LIMIT SIGNALING LIMIT (RESISTANCE (RESISTANCE DESIGN CRITERIA)DESIGN CRITERIA)– REFERS TO THE DC REFERS TO THE DC

VOLTAGE DROP (IR VOLTAGE DROP (IR DROP) DUE TO THE DROP) DUE TO THE RESISTANCE OF RESISTANCE OF THE SUBSCRIBER’S THE SUBSCRIBER’S LOOPLOOP

– 20-80 mA (TYPICAL 20-80 mA (TYPICAL CURRENT RANGE)CURRENT RANGE)


BASIC RESISTANCE BASIC RESISTANCE DESIGNDESIGN

RDC =

0.1095d2

R – LOOP RESISTANCE (OHMS/MILE)

d - DIAMETER OF THE CONDUCTOR (INCH)


METHODS OF INCREASING METHODS OF INCREASING THE LOOP LENGTHTHE LOOP LENGTH

• USED A LARGER WIREUSED A LARGER WIRE

• USED OF LINE AMPLIFIERS USED OF LINE AMPLIFIERS AND/OR LOOP EXTENDERSAND/OR LOOP EXTENDERS

• USED OF INDUCTIVE LOADINGUSED OF INDUCTIVE LOADING


EFFECTS OF LOADING EFFECTS OF LOADING COILCOIL

• REDUCTION IN AC LOSSREDUCTION IN AC LOSS• UNIFORMITY IN ATTENUATIONUNIFORMITY IN ATTENUATION• INCREASE IN Zo THUS INCREASE IN Zo THUS

IMPROVING THE ECHO RETURN IMPROVING THE ECHO RETURN LOSSLOSS

• DECREASED IN VELOCITY OF DECREASED IN VELOCITY OF PROPAGATIONPROPAGATION

• LOWERS THE BANDWIDTHLOWERS THE BANDWIDTH


EXAMPLE PROBLEMEXAMPLE PROBLEM

• Determine the additional length of the Determine the additional length of the subscriber loop in a telephone system subscriber loop in a telephone system using cable from non-loaded to a loaded using cable from non-loaded to a loaded cable with the following specifications:cable with the following specifications:

AWG No.24: R=123AWG No.24: R=123ΩΩ/km, /km, αα=1.21 dB/km =1.21 dB/km (non-loaded); R=127(non-loaded); R=127ΩΩ/km, /km, αα=0.56 dB/km =0.56 dB/km (loaded): allowable loss=8dB:Tel. (loaded): allowable loss=8dB:Tel. Resistance=200Resistance=200ΩΩ, Loading Coil R=15, Loading Coil R=15ΩΩ

Resistance Limit = 1800 Resistance Limit = 1800 Assume one-point loading.Assume one-point loading.


NOISE IN TELEPHONE NOISE IN TELEPHONE SYSTEMSYSTEM

• THERMAL NOISETHERMAL NOISE

• INTERMODULATION NOISEINTERMODULATION NOISE

• CROSSTALKCROSSTALK– INTELLIGIBLE (AT LEAST 4 WORDS ARE INTELLIGIBLE (AT LEAST 4 WORDS ARE

UNDERSTANDABLE IN AN EXTRANEOUS UNDERSTANDABLE IN AN EXTRANEOUS CONVERSATIONS IN A 7 SECOND PERIOD)CONVERSATIONS IN A 7 SECOND PERIOD)

– UNINTELLIGIBLEUNINTELLIGIBLE

• IMPULSE NOISEIMPULSE NOISE


CROSSTALK COUPLINGCROSSTALK COUPLING

• THE DIFFERENCE IN THE POWER THE DIFFERENCE IN THE POWER LEVEL BETWEEN THE DISTURBING LEVEL BETWEEN THE DISTURBING PAIR AND THE DISTURBED PAIRPAIR AND THE DISTURBED PAIR

• USUALLY EXPRESSED IN dBUSUALLY EXPRESSED IN dB• FAR-END CROSSTALKFAR-END CROSSTALK

– AMOUNT OF COUPLING AT THE FAR END AMOUNT OF COUPLING AT THE FAR END OF THE LINEOF THE LINE

• NEAR-END CROSSTALKNEAR-END CROSSTALK– AMOUNT OF COUPLING AT THE POINT AMOUNT OF COUPLING AT THE POINT

WHERE THE TONE GENERATOR IS WHERE THE TONE GENERATOR IS INSERTEDINSERTED


TEST TONETEST TONE

• A TEST TONE IS A PURE SIGNAL AT A A TEST TONE IS A PURE SIGNAL AT A SIGNAL FREQUENCY AND POWER SIGNAL FREQUENCY AND POWER LEVEL. LEVEL.

• REFERENCE TEST TONE = 1000 Hz, REFERENCE TEST TONE = 1000 Hz, 1mW APPLIED AT THE POINT OF ZERO 1mW APPLIED AT THE POINT OF ZERO RELATIVE LEVEL (0 dB)RELATIVE LEVEL (0 dB)

• BASED ON TEST MADE, 1kHz PRODUCE BASED ON TEST MADE, 1kHz PRODUCE MORE INTERFERENCE THAN ANY MORE INTERFERENCE THAN ANY OTHER FREQUENCIES IN THE VOICE OTHER FREQUENCIES IN THE VOICE CHANNELCHANNEL


DIIFFERENT NOISE DIIFFERENT NOISE UNITSUNITS

• REFERENCE NOISEREFERENCE NOISE– IS THE POINT OF ZERO IS THE POINT OF ZERO

INTERFERENCEINTERFERENCE• dBdBrnrn

– Noise measured base on Noise measured base on the old 144 Handsetthe old 144 Handset

– -90 dBm, 1kHz-90 dBm, 1kHz• dBadBa

– Based on F1A handsetBased on F1A handset– Adjusted reference noiseAdjusted reference noise– -85 dBm, 1 kHz-85 dBm, 1 kHz

• dBa0dBa0– The measurement of noise The measurement of noise

referred to a test point of 0 referred to a test point of 0 dBmdBm

– The reading if the test tone The reading if the test tone level is 0 dBm at the point level is 0 dBm at the point where the reading is being where the reading is being made.made.

• dBrnCdBrnC– Based on type 500 handset or Based on type 500 handset or

the C-message weighting the C-message weighting curvecurve

• dBrnC0dBrnC0– Same as dBa0Same as dBa0

• Picowatts,Psophometrically Picowatts,Psophometrically weighted (pWp)weighted (pWp)– Refers to noise measurement Refers to noise measurement

expressed in pWexpressed in pW


CONVERSION OF NOISE CONVERSION OF NOISE UNITSUNITS

dBa = dBm (pure test tone) + 85dBa = dBm (F1A weighted) + 82dBa0 = dBa - (test point level)dBrnC = dBa + 6

dBrnC0 = dBrnC – (test point level)dBrnC = 10 log pWp


SYSTEM ENGINEERINGSYSTEM ENGINEERING

• TRAFFIC ENGINEERINGTRAFFIC ENGINEERING• PLANT ENGINEERING PLANT ENGINEERING

(INSIDE / OUTSIDE)(INSIDE / OUTSIDE)• TRANSMISSION TRANSMISSION

ENGINEERINGENGINEERING• EQUIPMENT ENGINEERINGEQUIPMENT ENGINEERING


PLANNINGPLANNING

• Traffic Study (Initial Planning)Traffic Study (Initial Planning)• Technical Quality / Operating Technical Quality / Operating

CharacteristicCharacteristic– Grade of Service / ReliabilityGrade of Service / Reliability– Transmission Requirements / FacilitiesTransmission Requirements / Facilities

• TestingTesting• InstallationInstallation• Fine TuningFine Tuning


TRANSMISSION TRANSMISSION ENGINEERINGENGINEERING

• ATTENUATION ATTENUATION DISTORTIONDISTORTION– RESULT OF AN RESULT OF AN

IMPERFECT IMPERFECT AMPLITUDE-AMPLITUDE-FREQUENCY FREQUENCY RESPONSE OF THE RESPONSE OF THE SYSTEMSYSTEM

• ENVELOPE DELAYENVELOPE DELAY– THE DERIVATIVE OF THE DERIVATIVE OF

PHASE SHIFT WITH PHASE SHIFT WITH RESPECT TO RESPECT TO FREQUENCYFREQUENCY

• ENVELOPE DELAY ENVELOPE DELAY DISTORTIONDISTORTION– MAXIMUM MAXIMUM

DIFFERENCE IN THE DIFFERENCE IN THE DERIVATIVE OVER DERIVATIVE OVER ANY FREQUENCY ANY FREQUENCY INTERVAL INTERVAL

– MEASURED IN ms or MEASURED IN ms or usus

• POWER LEVELPOWER LEVEL– VOICE: S/N = 30 dBVOICE: S/N = 30 dB– VIDEO: S/N = 45 dBVIDEO: S/N = 45 dB– DATA: 15 dBDATA: 15 dB


TRUNKTRUNK

• TRUNKTRUNK– IS A VOICE IS A VOICE

CIRCUIT CIRCUIT CONNECTING CONNECTING TWO SWITCHING TWO SWITCHING CENTERSCENTERS

• DIRECT TRUNKDIRECT TRUNK– INTERCONNECTS INTERCONNECTS

TWO CLASS FIVE TWO CLASS FIVE END OFFICESEND OFFICES

• TOLL CONNECTING TOLL CONNECTING TRUNKTRUNK– CONNECTS A CLASS CONNECTS A CLASS

5 END OFFICE TO 5 END OFFICE TO ANY HIGHER ANY HIGHER RANKING TOLL RANKING TOLL OFFICEOFFICE

• INTER-TOLL INTER-TOLL TRUNKTRUNK– CONNECTS ANY CONNECTS ANY

CLASS 1 THROUGH CLASS 1 THROUGH FOUR TOLL FOUR TOLL SWITCHING OFFICE SWITCHING OFFICE TO ANY OTHER TO ANY OTHER CLASS 1 THROUGH CLASS 1 THROUGH THE FOUR OFFICETHE FOUR OFFICE


HIERARCHIAL HIERARCHIAL STRUCTURESTRUCTURE

• NORTH AMERICANNORTH AMERICAN– CLASS 1. REGIONAL CLASS 1. REGIONAL

CENTERCENTER– CLASS 2. CLASS 2.

SECTIONAL CENTERSECTIONAL CENTER– CLASS 3. PRIMARY CLASS 3. PRIMARY

CENTERCENTER– CLASS 4. TOLL CLASS 4. TOLL

CENTERCENTER– CLASS 5. END CLASS 5. END

OFFICEOFFICE

• CCITTCCITT– CLASS 1. CLASS 1.

QUATERNARY QUATERNARY CENTERCENTER

– CLASS 2. TERTIARY CLASS 2. TERTIARY CENTERCENTER

– CLASS 3. CLASS 3. SECONDARY SECONDARY CENTERCENTER

– CLASS 4. PRIMARY CLASS 4. PRIMARY CENTERCENTER

– CLASS 5. LOCAL CLASS 5. LOCAL CENTERCENTER


SWITCHING SWITCHING HIERARCHYHIERARCHY

1 1

2 2

5 5

4

3 3

VNL(MAX:2.5dB)

VNL(MAX:2.5dB)

VNL(MAX:2.9dB)

VNL+2.5 (MAX:5.5dB)

VNL(MAX:1.4dB)

0 dB(MAX:0.5dB)

4


VIA NET LOSS DESIGNVIA NET LOSS DESIGN

• THE TELEPHONE THE TELEPHONE SYSTEM MUST SYSTEM MUST PROVIDE SMALL PROVIDE SMALL TRANSMISSION TRANSMISSION LOSS TO GIVE LOSS TO GIVE NATURAL RECEIVED NATURAL RECEIVED VOLUMES AND VOLUMES AND MINIMUM MINIMUM CONTRAST IN CONTRAST IN RECEIVED VOLUMES RECEIVED VOLUMES FROM CALL TO CALLFROM CALL TO CALL

• THE TELEPHONE THE TELEPHONE SYSTEM MUST SYSTEM MUST PROVIDE HIGH PROVIDE HIGH TRANSMISSION TRANSMISSION LOSS TO ENSURE LOSS TO ENSURE SATISFACTORY SATISFACTORY PERFORMANCE PERFORMANCE FROM THE FROM THE STANDPOINT OF STANDPOINT OF TALKER ECHO AND TALKER ECHO AND NEAR SINGINGNEAR SINGING


VNL FORMULAVNL FORMULA

VNL = VNLF (1-WAY LENGTH OF TRUNK, mi) + 0.4 dBVNL = 0.20t + 0.4 dBVNLF = 0.204 / VELOCITY dB/mi

VNLF – VIA NET LOSS FACTOR

t – delay time in ms


VNLFVNLF

VNLF (dB/mi)

VNLF (dB/mi)

2-WIRE 4-WIRE

TOLL CABLE: 19H172-63 & 16H172 -63 19B88-50 (SIDE & PHANTOM) 19H88-50 (SIDE & PHANTOM) 19H44-25 & 16H44-25

0.040.040.030.02

0.020.020.0140.01

VOICE FREQQUENCY OPEN WIRE 0.01

CARRIER / MICROWAVE RADIO 0.0015

VOICE FREQUENCY (LOADED & NON-LOADED)

0.04 0.017


CATEGORICAL LEVELS OF CATEGORICAL LEVELS OF LOSS USED IN DDDLOSS USED IN DDD

• TOLL CONNECTING TOLL CONNECTING TRUNKS: VNL + 2 TRUNKS: VNL + 2 dBdB

• INTERTOLL TRUNK INTERTOLL TRUNK WITHOUT ECHO WITHOUT ECHO SUPPRESSOR: VNLSUPPRESSOR: VNL

• INTERTOLL INTERTOLL TRUNKS WITH TRUNKS WITH ECHO ECHO SUPPRESSOR: 0 dBSUPPRESSOR: 0 dB

• ECHO ECHO SUPPRESSORSUPPRESSOR– AN ELECTRONIC AN ELECTRONIC

CIRCUIT CIRCUIT INSERTED IN THE INSERTED IN THE FOUR WIRE FOUR WIRE TRUNK PATH TO TRUNK PATH TO EFFECTIVELY EFFECTIVELY BLOCK THE BLOCK THE PASSAGE OF PASSAGE OF REFLECTED REFLECTED SIGNALSIGNAL


TELEPHONE TRAFFICTELEPHONE TRAFFIC• TRAFFICTRAFFIC

– REFERS TO THE REFERS TO THE AGGREGATE OF ALL AGGREGATE OF ALL USER REQUESTS USER REQUESTS BEING SERVICED BY BEING SERVICED BY THE NETWORKTHE NETWORK

• CALLCALL– AN ACTUAL AN ACTUAL

ENGAGEMENT OR ENGAGEMENT OR SEIZURE OF A SEIZURE OF A CIRCUITCIRCUIT

• ATTEMPTATTEMPT– ANY EFFORT ON THE ANY EFFORT ON THE

PART OF A TRAFFIC PART OF A TRAFFIC SOURCE TO SEIZE A SOURCE TO SEIZE A CIRCUITCIRCUIT

• BUSY HOURBUSY HOUR– THE CONTINUOUS 1 THE CONTINUOUS 1

HOUR OF THE DAY HOUR OF THE DAY DURING WHICH THE DURING WHICH THE HIGHEST USAGE HIGHEST USAGE OCCURSOCCURS

• CALL CALL CONCENTRATIONCONCENTRATION– RATIO OF THE BUSY RATIO OF THE BUSY

HOUR CALLS TO THE HOUR CALLS TO THE TOTAL DAY CALLSTOTAL DAY CALLS

• HOLDING TIMEHOLDING TIME– LENGTH OF TIME LENGTH OF TIME

WHICH A CALL WHICH A CALL ENGAGES A TRAFFIC ENGAGES A TRAFFIC CHANNELCHANNEL


TRAFFIC UNITTRAFFIC UNIT• CALL HOURCALL HOUR

– QUANTITY QUANTITY REPRESENTING 1 OR REPRESENTING 1 OR MORE CALLS HAVING AN MORE CALLS HAVING AN AGGREGATE DURATION AGGREGATE DURATION OF 1 HOUROF 1 HOUR

• CALL SECONDCALL SECOND– QUANTITY REPRESENTED QUANTITY REPRESENTED

BY 1 OR MORE CALLS BY 1 OR MORE CALLS HAVING AN AGGREGATE HAVING AN AGGREGATE DURATION OF 1 SECONDDURATION OF 1 SECOND

• CENTI-CALL CENTI-CALL SECOND(CCS) OR (HCS)SECOND(CCS) OR (HCS)– THE QUANTITY THE QUANTITY

REPRESENTED BY 1 100-REPRESENTED BY 1 100-SECOND CALL OR BY AN SECOND CALL OR BY AN AGGREGATE OF 100 CSAGGREGATE OF 100 CS

• EQUATED BUSY HOUR EQUATED BUSY HOUR CALL (EBHC)CALL (EBHC)– THE AVERAGE THE AVERAGE

INTENSITY IN ONE OR INTENSITY IN ONE OR MORE TRAFFIC PATHS MORE TRAFFIC PATHS OCCUPIED IN THE BUSY OCCUPIED IN THE BUSY HOUR BY 1 TWO HOUR BY 1 TWO MINUTE CALLMINUTE CALL

• NOTE: THE MAXIMUM NOTE: THE MAXIMUM CAPACITY OF A SINGLE CAPACITY OF A SINGLE SERVER (CHANNEL) IS 1 SERVER (CHANNEL) IS 1 ERLANGERLANG


TRAFFIC CALCULATIONTRAFFIC CALCULATION

A = Cho / TA – TRAFFIC, ERLANG (E)C – NO OF CALLS

ho – AVERAGE HOLDING TIME (HR)T – TIME =1 HR

1 E = 30 EBHC = 36 CCS = 60 CM = 3600 CS


GRADE OF SERVICE, BGRADE OF SERVICE, B

B = An / n!

1 + A + A2/2! + A3/3! + . . . . . + An/n!

B – PROBABILITY THAT A CALL WILL BE LOST

A – TRAFFIC IN ERLANG

n – NUMBER OF CIRCUITS (E.G. TRUNK)


MULTIPLEXINGMULTIPLEXING

• FREQUENCY FREQUENCY DIVISION DIVISION MULTIPLEXING MULTIPLEXING (FDM)(FDM)– TRANSMISSION OF TRANSMISSION OF

MULTIPLE MULTIPLE SIGNALS OVER SIGNALS OVER THE SAME THE SAME CHANNEL AT CHANNEL AT DIFFERENT DIFFERENT FREQUENCY FREQUENCY BANDSBANDS

• CCITTCCITT– STANDARD GROUPSTANDARD GROUP

• 60-108 kHz, 12 VC60-108 kHz, 12 VC

– SUPERGROUPSUPERGROUP• 312 – 552 kHz, 5 312 – 552 kHz, 5

groupsgroups

– MASTERGROUPMASTERGROUP• 812 – 2044 kHz, 5 SG812 – 2044 kHz, 5 SG

– SUPERMASTERGROSUPERMASTERGROUPUP• 8519 – 12388 kHz8519 – 12388 kHz


MULTIPLEXINGMULTIPLEXING

• TIMED DIVISION TIMED DIVISION MULTIPLEXING MULTIPLEXING (TDM)(TDM)– TRANSMISSION TRANSMISSION

OF MULTIPLE OF MULTIPLE SIGNALS AT THE SIGNALS AT THE SAME SAME FREQUENCY BUT FREQUENCY BUT AT DIFFERENT AT DIFFERENT TIME INTERVALSTIME INTERVALS

LINE LINE TYPETYPE

DIGITAL DIGITAL SIGNALSIGNAL

BIT BIT RATE RATE (MBPS(MBPS

))

CAP CAP (VC)(VC)

T1T1

T1CT1C

T2T2

T3T3

T4T4

T5T5

DS1DS1

DS1CDS1C

DS2DS2

DS3DS3

DS4DS4

DS5DS5

1.5441.544

3.1523.152

6.3126.312

46.30446.304

274.17274.1766

560.16560.16

2424

4848

9696

672672

40324032

80648064

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