Call Setup

CP

(5)

(7)

(7)

(5)

(6)

(1)

A-SUB

B-SUB

SLCA DIUD

SLMCP

DIUGS

(2)

(3)

LIU

SUTOG

CR

GP

DLUC

SLCA DIUD

SLMCP

DIUGS

(5)

LIU

SUTOG

CR

GP

DLUC

MBU:LTG MBU:SGC

IOP:MB

SGC

(1)Off-hook(2)Dial tone (3)Dialing information (4)Ringing current to called party(5)Ring-back to calling party(6)Answer (7)Set up connection Control signals

Fig. 1.1 : Block diagram of an internal call set-up (for a DTMF subscriber)

A-LTGA-DLU SN

B-DLU B-LTG

(4)

(a) Outgoing call (Originating traffic) (b) Incoming call (Terminating traffic) (c) Internal call (d) Transit call

Transit exchange

Terminating exchange (B-EX)

Originating exchange (A-EX)A-side B-side

(c) (a)

SN

SGC

DLU

DLUC

A-LTG

GP

B-LTG

GP

DLU

DLUC

CP

A-SUB B-SUB

A-SUB

A-side B-side

(d)

SN

SGC

DLU

DLUC

A-LTG

GP

B-LTG

GP

DLU

DLUC

CP

A-side B-side

(b)

SN

SGC

DLU

DLUC

A-LTG

GP

B-LTG

GP

DLU

DLUC

CP

B-SUB

Fig 1.2 : Different types of calls in an EWSD exchange

Event State

Seizure A/AD

Digit block

Release A

Release B

Disconnect Permanent Inter-mediate call duration

Call diversion

Channel idle OPCSPSZ I I I I OPCSPOP I I

Port A Seized OPCSSHA OPCSDTS OPCSRTS I I OPCSPOP I OPCSICF

Port A receiving

OPCSSHA OPCSDTR OPCSRTR I I OPCSPOP I OPCSICF

Port A to Port B

I OPCSZDB OPCSRSA I OPCSDIS OPCSPOP OPCSICD OPCSICF

Port B from Port A

OPCSSZB I I OPCSRBP OPCSPOP I I

Port A wait for disconnect

I I OPCSRHR I

Port A to announcement

I I OPCSRTA I

ANN from port A

OPCSSTA I I I

Port A wait for release

I I OPCSRWR I

Port B wait for release

OPCSSNA I I OPCSRBF

Wait for SCI response

I I OPCSRWR I

Equipment NAC

OPCSSNA I I I

Channel MTC-busy

OPCSSMB I I I

ACL seized OPCSSNA OPCSDAS I I

ACL receiving OPCSSNA OPCSDAR I I

Wait for prepare test access acknowledgmet

OPCSGLA I I I

I

OPCSDIS

OPCSDIS

I

OPCSDIS

I

OPCSDIS

I

I

OPCSDTA

OPCSDTA

OPCSDTB

OPCSPOP

OPCSPOP

OPCSPOP

OPCSPOP

OPCSOPO

OPCSPOP

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I = Illegal linkage: the fault-induced step table OPCSRIC is called.Fig 2.1 : Extract from State/event table

B-DLUCB-GPCPA-GPA-DLUC

Fig. 2.2 : Sequence of data memory seizures for an internal call

Seizure

BD

Ring back

(COC)

On-hook

On-hook

Busy toneIdle

Release A

Clear forward

Answer

Ringback

Set up

Complete

Set up SN

Digit block

Seizure AD

Dial tone

nth digit

1st digit

Off hook

B-CREG

x

A-CREG

A-CREG

B-CHR

B-CHR

x

A-CHR

Meter pulses

A-CREG

A-CREG

x

A-CHR

x

B-CHR

Release B

Calling

Subscriber

A-SUB

Called

Subscriber

B-SUB

Off-hook

Ringing

B-CHR

CPB

x

B-CREG

Release/idlex

Wait for releaseChange meter1)

SeizedPort A receivingPort A to port B or port B from port A

CPB

B-CHR

1)

Continued in Fig. 3.1(b)

(4)

(5)

(8)(9)

(10) IT (13)

(15)

(17)

(19)

(3)

(7)

(2)

(11)

(16)

(6)

(20)

(21)

Originating Exchange (A-EX)CPA-GPA-DLUCA-SLMCP

A-Sub

(a) Channel Idle(1)

Off hook Seizing Seizure AD

Seizure AD

(b) Port A seized

Set up

Dial tone(12)

Dial tone

(14) 1st digit

Disconnect dial tone

Digit(18)

Digit

Digit

Digit block

Come again(c) Port A receiving

( ) Call-processing statesSubscriber action

Commands, messages, reports, line signalsMessage flow in the processor

Audible tonesFig. 3.1(a) : Outgoing Call setup ( Message flow representation )

(23)

(30)

COC

(31)

(32)

Set up


(28)

(33)(34)(35)

(38) (39)

(42)

(e) Port A to port B

(24) (25) (26)

(27)

(29)

Originating Exchange (A-EX)A-GP

Continued from Fig. 3.1 (a) Digits (22)

Digits

(36)

CP B-GP BT

(d) Port B from port A

Set up complete

Seizure B T

Digits

Digit transfer

Digits

(40)Address complete

Address complete

Set up SN

Seizure BT

( ) Call-processing states

Fig. 3.1(b) : Outgoing Call setup (contd.) ( Message flow representation )

SGC

(41)

(37)

ZONE INDEX

Fig. 3.2(a) : Outgoing Call setup( Block Diagram representation )

(20)(5)

SNA-LTG (8) (8)

A-DLUGS

DIUSLM LIU

SUTOG

CR

A-GP

SLCA

SLMCP

DIUD

DLUC

(4)(3)(15)

(3) (15) (18)CREG

(5)(19)

(21)(21)

(21)(5)(19)

(5)(19)

(21)

(21)(8)

(8)

B-LTGGS

DIULIU

SUTOG

CR

SGCB-GP

CPMBU:SGCMBU:LTG

B-EX

CREG

B-CHRCPBA-CHR

(5)(19)

(1) (12)(14)(18)

(8)

(4)

(3)

(8)

(4)(3)

(2)(7)(11)(16)(2)

(7)(9)

A-SUB

(6)(21)

IOP:MB

Fig. 3.2(b) : Outgoing Call setup (contd.)( Block Diagram representation )

(23)

SNA-LTG (31) (31)

A-DLUGS

DIUSLM LIU

SUTOG

CR

A-GP

SLCA

SLMCP

DIUD

DLUC

TPAG

TPAEC

(31)

(31)

(30)

(30)

(22)

(22) (30) (36)CREG

(23)(32)(37)

(27)(29)

(27)(29)

(29)(30)

(23)(30)(32)(37)

(23)

(29)(30)(41)

(29)(30)(41)

(31)

(35) (39)

(40)

(30)

B-LTG (42) (42)

GSDIU

LIU

SUTOG

CR

SGCB-GP

CPMBU:SGCMBU:LTG

B-EX

(42)

(42)

(30)

(40)

(28) (33) (38)CREG

B-CHRCPBA-CHR

(41)

(27)(30)(32)(37)

(30)(41)

(27)(32)(37)

(42)(35)(39)

(24)(25)

(26)(23)

(22)(36)

A-SUB

(27)

(30) (32) (37)

(30)(41)

(27)(29)

(34)

IOP:MB

(2)

(4)

(5) (8)

(10)(11)(12)

(14)

(6) (7)

(15)

(16)

(19)(20)


B-GPCPA-GPA-T

(1)Seizing Seizure A

(9) 1st digit

Digit acknowledg ment

(13) Digit

Fig. 4.1(a) : Incoming Call setup ( Message flow representation )

Commands, messages, reports, line signals

Message flow in the processor

4 INCOMING CALL CONTROL (Terminating Traffic)

(a) Channel idle

Seizure Acknowledgement

(b) Port A seized

Digit block

Come again

(17) Digit (18)Digit block


Continued

in Fig. 4.2

B-SUBAT B-SLMCPB-DLUC


Audible tonesCommands, messages, reports, line signalsMessage flow in the processorSubscriber action

CPA-GP B-GP

(22)

(21)

(23)(24)

Set up SN

Seizure BD

Seizure BD

(26)

(25)(27)(28)Set up

(29)

(COC) Port A to Port B

(e) Port B from Port A

Setup Complete

(30)

(31)

(32)

Address complete

Ring-back

Ring-back

(35)

(33) Ringing(34)

Ringing 1st ring

Subsequent ringing

(36)Off

hook

Answer

(37)(38)Answer

(39)

Answer Signal


Fig. 4.1b: Incoming call ( contd. )

Continuedfrom Fig. 4.1

B-LTG

SN

A-EX

(5) (10)

(1) (9) (11) (13) 17)

GS

SU

LIUDIU

CR

TOG

CREG (2) (9) (13) (17)

(3) (9) (13) (17) A-GP

(8)(10)(12)

(4)(14)(18)

CP

(16)(18)(4)(14)

(6)(19)(20)

(4)(14)(18)

(4)(14)(18)

(14)

(16)

(16)(16)

(16)

(16)(15) (1) (4)

A-LTG

(8)(8)

SGC

SLM

MBU:LTG

B-CHRCPBA-CHR

IOP:MB

MBU:SGC

GS

SU

LIUDIU

CR

TOG

CREG

B-GP

A-DLU

B-SUB

SLCA

SLMCP

DIUD

DLUC

Fig. 4.2a : Incoming call - Block Diagram Representation

21

(27)

(35)(37)

(35)

(27)

(27)

(37)(27)(37)(27)

GS

SU

LIU

(29)

DIU

CR

TOG

CREG

B-GP

(38)(22)(31)

(23)

(24)(33)

(27)(35)(37)

B-LTG

SN

(28)

(22)

A-EX(32) (35) (39)

GS

SU

LIU

(29)

(29)

(35)

DIU

CR

TOG TPAEC

TPAG

CREG

A-GP

(31)(29)(28)(38)

(21)(28)(29)(35)(38)

(21)(29)(31)

(22)(28)

(32)(39) (30)

(30)

(30)(35)

A-LTG(30)(35)(30)

(24)(33)

(26)(34)

(27)

(27)

CP

(21)(22)(29)(31)

(21)(29)(35)(38)

B-SUB

(34)(36)

(27) (27)

(24)(33)

(21)(28)(29)(35)(38)

(22)(28)

SGC

SLM

SLCA

SLMCP

DIUD

DLUC

B-CHRCPBA-CHR

IOP:MB

MBU:SGCMBU:LTG

Fig. 4.2b : Incoming call - Block Diagram Representation ( contd)

(21)(29)(31)

(21)(29)(35)(38)

B-DLU

(21)(22) (28)

Subscriber action

Message flow in the processorCommands, messages, reports, line signals

BTB-GPCPA-GPA-DLUC

Originating exchange (A-EX)A-SUB A-SLMCP

Clear forward

Clear forward

Clear forward

On-hook

(2) (3)

(4)

(7)

(8)

(5)

(6)

(11)

(12)

(9)

(13)


(1)

Idle(10)

Release B

(b) Channel idle (B-CHR)

(a) Channel idle (A-CHR)

Clear forward Acknowledgment

Release A

Fig. 5.1 Call clearing by the calling subscriber

Subscriber action

Message flow in the processorCommands, messages, reports, line signals

B-SUBB-SLMCPB-GPCP

Terminating exchange ( B-EX )A-T A-GP

Clear Back

Clear Back

On hook

Clear back (5)

(6)

(4)

(7)

(11)

(12)

(2)

(9)

(3)

(8)

(10)


Release B

(b) Channel idle (B-CHR)

Idle B

Fig. 5.1 Call clearing by the called subscriber

B-DLUC

Clear Forward

(a) Port A wait for release

Idle BAcknowledgement

Release B

(13)

(14)

ClearForward

(15)

(16) (17)

(c) Channel idle (A-CHR)

B-SUBA-SUB B-DLUCA-DLUC

IT

Dial tone

Off-hook

CPA-GP B-GP

(d) Port A to port B

(c ) Port B from port A

(b) Port A seized

(a) Channel idle

Set up

Digit block

Set up SN

Seizure BD

Setup complete

Fig. 6.1 : Call setup ( internal call )

SGC

Last digit

1st digit

COC

Off-hook

Ringing

Audible tonesCommands, messages, reports, line signalsMessage flow in the processorSubscriber action

Answer

Audible ringing


AT A-GP

Seizing

Seizure Acknowledgement

Time out of interval

Timer

DigitsDigits

CP B-GP BT

(COC)(d) Port A to port B

(c ) Port B from port A

(b) Port A seized

(a) Channel idle

Set up

Digit block

Set up SN

Seizure BTSeizing

Setup complete



Fig. 7.1 : Transit call control

SGC

1st digit

3rd digit

Digits

Digits

Message structures for Exchange of information for call control :

Every call setup is controlled with the aid of information messages, i.e. commands, messages, reports and orders. Message channels composed of the following subsections are provided for the transmission of these information messages : - SDC:LTG between the LTG and the SN.- SDC:TSG between the MBU:LTG and the SN.- SDC:SGC between the MBU:SGC and the switch group control (SGC).- Semipermanently switched message channels in the switching network.- Bus system B:MBG between the MB (here: an MBG) and the CP.

Figure 8.1 shows the basic structure of a message block, for the transmission of the message block via the message channels the HDLC transmission procedure is used.

All information message required for successfully setting up an internal call are numbered 1 to 10 in Fig. 8.2.The

structural layout of the HDLC procedures of these messages is shown in Tables 8.1 through 8.10.

Cyclic data verification

Information fieldControl field

Address field

Separator (flag)

Separator (flag)

Opening field Closing field

011111102 bytesmax. 27 bytes

Fig. 8.1 : Structure of a message block

1 byte1 byte01111110

Fig. 8.2 : Flow of information messages for call control ( Internal Call )

B-SUBB-DLUCB-GPCPA-GPA-SUB A-DLUC

Dial tone

Digit 1

Digit 2

Digit n

(3)

Off-hook

Ringback

Off-hook

On-hook

Idle

On hook

Seizure AD (1)

Set up SN

Digit block (2)

Seizure BD(4) Set up

Setup complete (5) Ringing

Busy tone

Answer (6)

Clear forward (7)

Clear forward acknowledgment (8)

Release A D(9)

Release B D(10)

(1)

SGC

Commands, messages, reports, line signals

Audible tones

Subscriber action

COC

MeterPulses

Call Setup

Documents

Transcript of Call Setup