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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
Commands, messages, reports, line signalsMessage flow in the processor
(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)
Terminating exchange (B-EX)
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
( ) Call-processing states
Continued
in Fig. 4.2
B-SUBAT B-SLMCPB-DLUC
Terminating exchange (B-EX)
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
( ) Call-processing states
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)
( ) Call-processing states
(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)
( ) Call-processing states
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
( ) Call-processing states
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
( ) Call-processing states
Commands, messages, reports, line signalsMessage flow in the processor
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