Call Setup

(1)

A-DLU SLCA

DIUD

A-SUB

GS

DIU

DLUC

LIU

(5) (7)

(2)

SU TOG SLMCP

SN

A-LTG

CR

(3) GP

(6)

B-DLU SLCA

DIUD

B-LTG GS

DIU

LIU

(7) (5)

B-SUB

SU TOG SLMCP

DLUC

(5)

CR (4)

GP

SGC

CP (1)Off-hook (2)Dial tone (3)Dialing information MBU:SGC MBU:LTG (4)Ringing current to called party (5)Ring-back to calling party IOP:MB (6)Answer (7)Set up connection Fig. 1.1 : Block diagram of an internal call set-up (for a DTMF subscriber) Control signals

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

DLU A-SUB

B-side B-LTG (c) DLU

SN

B-SUB

DLUC (a) GP

A-SUB

SGC

D LUC

GP

CP

Transit exchange A-side A-LTG

DLU

B-side B-LTG DLU

SN

DLUC GP

SGC

D LUC

GP

(d) CP

Terminating exchange (B-EX) DLU

A-side A-LTG

SN

B-side B-LTG DLU

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

SGC

GP

D LUC

B-SUB

CP (b)

Fig 1.2 : Different types of calls in an EWSD exchange

Seizure A/AD

Digit block

Release A

Release B

Disconnect

Permanent

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

I

OPCSPOP

I

I

Port A wait for disconnect

I

I

OPCSRHR

I

OPCSDIS

OPCSPOP

I

I

Port A to announcement

I

I

OPCSRTA

I

OPCSDIS

OPCSPOP

I

I

ANN from port A

OPCSSTA

I

I

I

I

OPCSPOP

I

I

Port A wait for release

I

I

OPCSRWR

I

OPCSDIS

OPCSPOP

I

I

Port B wait for release

OPCSSNA

I

I

OPCSRBF

I

OPCSOPO

I

I

Wait for SCI response

I

I

OPCSRWR

I

OPCSDIS

OPCSPOP

I

I

Equipment NAC

OPCSSNA

I

I

I

I

I

I

I

Channel MTCbusy

OPCSSMB

I

I

I

I

I

I

I

ACL seized

OPCSSNA

OPCSDAS

I

I

OPCSDTA

I

I

I

ACL receiving

OPCSSNA

OPCSDAR

I

I

OPCSDTA

I

I

I

Wait for prepare test

OPCSGLA

I

I

I

OPCSDTB

I

I

I

Event

Inter-mediate call duration

Call diversion

State

access acknowledgmet

= Illegal linkage:

the fault-induced step table OPCSRIC is called.

A-DLUC

A-GP

CP

ACREG

Off hook

Seizure AD

B-GP

B-DLUC

B-CHR

Dial tone 1st digit

ACREG

Digit block

CPB

nth digit B-CHR

Set up SN

C a l l i n g S u b s c r i b e r

C a l l e d

Seizure B-CHR

BD

BCREG

A-CHR

Set up Ring back

(COC)

CPB

x Ringback

Complete

Ringing Off-hook

Answer

Meter pulses

ACREG

On-hook Idle

AS U B

ACREG x

Clear forward Release A

Busy tone

BS U B

B-CHR A-CHR

x B-CHR

x 1)

Seized Port A receiving Port A to port B or port B from port A

x

Release B BCREG x

S u b s c r i b e r

On-hook

Release/idle

Wait for release 1) Change meter

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

Originating Exchange (A-EX)

A-SLMCP A-Sub Off hook

(2)

A-GP

A-DLUC

Seizing

(3)

Seizure AD

(1)

(4)

CP

(a) Channel Idle

(5) (7)

(6)

Seizure AD

(8) (9) (11) (12)

Set up

Dial tone

Dial tone

(16) (14)

(10) IT (13)

(b) Port A seized

(15) (17)

(19)

1st digit Disconnect dial tone

(18)

Digit Digit

(20)

Digit Digit block

(21)

Come again (c) Port A receiving

( ) Call-processing states Subscriber action Message flow in the processor Commands, messages, reports, line signals Audible tones

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

Continued in Fig. 3.1(b)

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

Originating Exchange (A-EX) CP

A-GP

BT

B-GP

SGC (24) (25) Set up SN (26) Seizure BT

(23)

(d) Port B from port A (27) ZONE INDEX Set up (e) Port A to port B (30)

(28)

(29)

COC Seizure B T

(31) Set up complete (32)

Digits (33) (34) (35) Digits (36)

Digit transfer (37) Address complete

Digits (38) Address (40) (39) complete (42)

(41) ( ) Call-processing states Message flow in the processor Commands, messages, reports, line signals

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

(1)

(12) (14) (18)

A-DLU SLM

A-SUB

S (8) L C A (2) S L M C P

(7) (3) (11) (16)(2) (7) (9)

(8) (4)

D I U D

A-LTG (8) GS (8)

DIU

LIU

(21)

SN

(5) (19)

(3)

SU TOG

(21) (5) (19)

(8)

(21)

(4)

D L U C

(21)

CR (15)

(8)

(3) (4)

(21) (5) (19)

A-GP CREG (3) (15) (18)

B-EX

B-LTG GS

LIU

DIU SU TOG CR

B-GP

SGC

CREG

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

CP MBU:LTG MBU:SGC (5) (21) (6) (19) IOP:MB A-CHR CPB (5) (20)

B-CHR

(22) (36)

A-DLU SLM

A-SUB

S L C A

D I U D

S L M C P

D L U C

DIU

A-LTG (31) GS (31)

SU TOG

(31)

CR

(31)

(22)

(31)

T P A G T P A E C

(27) (29)

LIU

B-EX

(30)

(29) (30)

(30)

(23) (32) (41) (37)

( 30) ( 30) (32 ( 41) ) LIU (27) (30) (32) (37)

(30)

(42)

CR

(29) (30) (41)

(30)(29) (30)

B-LTG (42) GS (42)

SU TOG

( 27)

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

A-GP

DIU

(27) (29) (23)

CREG (22) (30) (36)

(35) (39) (40)

SN

(37 )

(30) (41)

(42)

(40) (35) (42) (39)

(34)(27) (32)

(41)

(37)

SGC

B-GP CREG (28) (33) (38) CP

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

MBU:SGC MBU:LTG (23) (27) (26) (24) (25) (29) IOP:MB A-CHR

CPB (23)

B-CHR

Terminating exchange (B-EX) A-GP

A-T

CP CALL CONTROL B-GP INCOMING (Terminating (a) Channel idle

Traffic)

(1)

Seizing

(2) (4)

Seizure A

(6) (7)

Seizure Acknowledgement (9) 1st digit Digit acknowledg ment

(5) (8)

(b) Port A seized

(10)

(11) (12)

(13)

(17)

Digit

Digit

(14)

(18)

Digit block

(15)

Come again

(16)

Digit block

(19) (20)

Continued in Fig. 4.2

( ) Call-processing states Message flow in the processor Commands, messages, reports, line signals

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

Terminating exchange (B-EX) AT

A-GP

CP

B-GP

B-DLUC

B-SLMCP B-SUB

Set up SN (21)

Continued from Fig. 4.1

(22)

Seizure BD (23) (24) (27)

Set up (28)

Seizure BD (25)

(29)

(COC) (30)

Address complete

(31)

(26)

Port A to Port B (e)

Port B from Port A

Setup Complete

(32) (33)

Ringing (34)

Ringback

Ringback

Ringing

Subsequent ringing (35)

Off hook Answer

Answer Signal

Answer

1st ring

(38) (37)

(39)

( ) Call-processing states Subscriber action Message flow in the processor Commands, messages, reports, line signals Audible tones

Fig. 4.1b: Incoming call ( contd. )

(36)

A-LTG (1) (9) (11) A-EX (13) 17)

DIU

(8) GS (8)

(16)

LIU

(5) (10)

(4) (14) (18)

CR

(14)

(15) (1) (4)

(8) (10) (12)

(3) (9) (13) (17) CREG

B

SUB

S L M C P

(4) (14) (18)

(16)

SU TOG

A-DLU SLM S L C A

(16)

SN

DIU D I U D D L U C

(16)

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

A-GP

(2) (9) (13) (17) B-LTG

LIU

GS SU TOG CR SGC B-GP CREG 21

MBU:LTG CP (4) (14)

(18)

(16)

IOP:MB A-CHR

CPB

MBU:SGC (6) (19) (20)

B-CHR

Fig. 4.2a : Incoming call - Block Diagram Representation

(32) (39)

A-EX

(35)

DIU

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

SU TOG CR

(30) (30) (35)

(32) (39) (30) A-GP

LIU T P (29) A G (29) T P A E C

(35)

(22) (28) (21) (28) (29) (35) (38)

(28) (22)

(21) (29) (31)

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

B-LTG

B-DLU

B-SUB

SLM

S L C A S L M C P

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

(21) (29) (31)

CREG

(34) (36)

(22) (28)

SN

(27)

DI (27) U D

(26) (24) (34) (33)

DL U C

(27) (27)

DIU

(24) (33)

SU TOG CR

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

GS

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

(29)

(35)

(27)

(27)

(35) (37)

(27) (24) (33)

LIU

(27) (35) (37)

(21) (29) (35) (38) (22) (38) (31)

B-GP CREG

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

SGC

(23)

CP MBU:LTG

MBU:SGC

(22) (28)

(21)

IOP:MB A-CHR

CPB

B-CHR

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

Originating exchange (A-EX) A-SUB

(1)

A-SLMCP

A-DLUC

CP

A-GP

B-GP

BT

On-hook

(2)

Clear forward

(3) (4)

Clear forward Clear forward

(5) Clear forward Acknowledgment

(6)

(7) (8)

Release A (9)

(a) Channel idle (A-CHR) (11) Idle

(13) Release(12)

(10)

B

(b) Channel idle (B-CHR) Subscriber action Message flow in the processor Commands, messages, reports, line signals

Fig. 5.1

( ) Call-processing states

Call clearing by the calling subscriber

Terminating exchange ( B-EX ) A-GP

A-T

CP

B-GP

B-DLUC

(3) Clear Back

Clear back (5)

B-SLMCP

(2) On hook

Clear Back

(4)

Clear (6) Forward (a) Port A wait for release

(7)

Idle B

(8) (10)

(11)

Idle B Acknowledgement

(9)

(12) Release B Clear Forward

(13)

(14)

(15)

(b) Channel idle (B-CHR)

Release B (16)

(17) (c) Channel idle (A-CHR)

Subscriber action

( ) Call-processing states

Message flow in the processor Commands, messages, reports, line signals

Fig. 5.1

Call clearing by the called subscriber

B-SUB

A-SUB

A-DLUC

A-GP

B-GP

B-DLUC

B-SUB

(a) Channel idle

Off-hook

Dial tone 1st digit

CP

(b) Port A seized IT

Last digit

Digit block

SGC

Set up SN Seizure BD (c ) Port B from port A Set up (d) Port A to port B COC

Setup complete

Ringing

Audible ringing Off-hook

Answer

Subscriber action ( ) Call-processing states Message flow in the processor Commands, messages, reports, line signals Audible tones

Fig. 6.1 : Call setup ( internal call )

AT

A-GP

CP

B-GP

BT

(a) Channel idle

Seizing

Seizure Acknowledgement

(b) Port A seized 1st digit

3rd digit Digit block

SGC Set up SN Seizure BT

Seizing

(c ) Port B from port A Set up (COC) Time out of interval Timer

(d) Port A to port B

Setup complete

Digits

Digits

Digits

Digits

( ) Call-processing states Message flow in the processor Commands, messages, reports, line signals

Fig. 7.1 : Transit call control

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 Opening the basic structure of a message block, for the transmission of the message block via the message field Closing field Separator Address (flag) field

Control field

field channels the HDLC transmission procedure isInformation used.

Cyclic data verification

Separator (flag)

All information message required1for successfully up an internal call are numbered 1 to 10 in Fig. 8.2.The 1 byte byte max.setting 27 bytes 01111110 01111110 2 bytes structural layout of the HDLC procedures of these messages is shown in Tables 8.1 through 8.10.

Fig. 8.1 : Structure of a message block

A-SUB

A-DLUC

A-GP

CP

B-GP

B-DLUC

B-SUB

Off-hook

(1)

Seizure AD (1) Dial tone

Digit 1 Digit 2

SGC Digit block (2)

Digit n

(4)

Set up

CO C

Set up SN Seizure BD (3)

Setup complete (5)

Ringing

Ring back

Off-hook Answer (6) Meter Pulses On-hook

Clear forward (7) Busy tone

Clear forward acknowledgment (8) Idle Release A D(9) Release B D(10) Subscriber action Commands, messages, reports, line signals Audible tones

On hook

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