03 tw2104eu01 eg0001 pstn protocol

8/13/2019 03 Tw2104eu01 Eg0001 Pstn Protocol

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PSTN Protocol Siemens

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Contents

1 PSTN Protocol 1

1 PSTN Protocol Message Types...................................................................3

2 PSTN Protocol Information Elements.........................................................13

3 PSTN Protocol Message Flow....................................................................32

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1 PSTN Protocol

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Siemens PSTN Protocol

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1 PSTN Protocol Message Types

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Message Type: ESTABLISH

Direction: Both

Information element Direction Type Length

Protocol $iscriminator %ot& M 1

'ayer 3 a$$ress %ot& M 2

Message type %ot& M 1

'ine#information (N to 'E ) 1

(*tonomo*s#signaling#se+*ence 'E to (N ) 1

,a$ence$#ringing 'E to (N ) 3

P*lse$#signal 'E to (N ) 3 to -

Stea$y#signal %ot& ) 3

Fig. 1 EST(%'IS message content

T&e EST(%'IS message s&all /e *se$ as an in$ication of eit&er an originating orterminating pat& re+*est.

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Message Type: ESTABLISH ACK

Direction: Both






P*lse$#signal %ot& ) 3 to -


Fig. 2 EST(%'IS (, message content

T&e EST(%'IS (, message s&all /e *se$ to acnowle$ge t&at t&e re+*este$action &as /een performe$ /y t&e entity.

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Message Type: SIGAL

Direction: Both





Se+*ence#n*m/er %ot& M 3

P*lse notification (N to 'E ) 1


Se+*ence#response (N to 'E ) 1

,a$ence$#ringing 'E to (N ) 3

P*lse$#signal %ot& ) -


igit#signal %ot& ) 3

eso*rce#*na4aila/le (N to 'E ) 3 to 5

Fig. 3 SI"N(' message content

!A"IG#TE: #nly one optional information element shall $e containe% in themessage an% shall $e han%le% as man%atory information element&

T&e SI"N(' message s&all /e *se$ to con4ey t&e PSTN line con$itions to t&e 'E6 or

to instr*ct t&e (N to esta/lis& specific line con$itions.

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Message Type: SIGAL ACK

Direction: Both





Se+*ence#n*m/er %ot& M 3

Fig. SI"N(' (, message content

T&e SI"N(' (, message s&all /e *se$ to acnowle$ge SI"N(' an$ P)T),)'P((METE messages.

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Message Type: STAT'S

Direction: A to LE


Protocol $iscriminator (N to 'E M 1

'ayer 3 a$$ress (N to 'E M 2

Message type (N to 'E M 1

State (N to 'E M 1

,a*se (N to 'E M 3 to -

Fig. - ST(T!S message content

T&e ST(T!S message s&all /e *se$ to in$icate t&e stat*s of t&e 7- PSTN protocolentity in t&e (N. T&is message s&all /e sent eit&er on re+*est /y a ST(T!SEN8!I9 message from t&e 'E or w&en t&e (N recei4es an *ne:pecte$ messagefrom t&e 'E.

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Message Type: DISC#ECT

Direction: Both






Fig. < IS,)NNE,T message content

T&e IS,)NNE,T message s&all /e *se$ to in$icate t&at t&ere is no call acti4ityan$ t&at t&e protocol entity in t&e (N can ret*rn to t&e N!'' state or it s&all /e *se$/y t&e (N to in$icate t&at t&e pat& s&all /e release$.

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Message Type: DISC#ECT C#M*LETE

Direction: Both





Stea$y#signal 'E to (N ) 3

Fig. 5 IS,)NNE,T ,)MP'ETE message content

T&is message s&all /e *se$ to acnowle$ge t&at t&e re+*este$ action &as /eenperforme$ /y t&e entity.

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Message Type: *"#T#C#L *A"AMETE"

Direction: LE to A


Protocol $iscriminator 'E to (N M 1

'ayer 3 a$$ress 'E to (N M 2

Message type 'E to (N M 1

Se+*ence#n*m/er 'E to (N M 3

ecognition#time 'E to (N )

Ena/le#a*tonomo*s#

acnowle$ge

'E to (N ) to ;

isa/le#a*tonomo*s#

acnowle$ge

'E to (N ) 3

Fig. = P)T),)' P((METE message content

!A"IG

N)TE> (t least one optional information element s&all /e containe$ in t&e message.It is only allowe$ to &a4e one of eac& information element in t&e message. W&enpro4i$e$ t&ese information elements s&all /e &an$le$ as man$atory informationelements.

T&e P)T),)' P((METE message s&all /e *se$ /y t&e 'E to c&ange aprotocol parameter in t&e (N.

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2 PSTN Protocol Information Elements

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T&e p*rpose of t&e P*lse#notification information element is to in$icate to t&e 'E t&at

a certain p*lse at t&e PSTN *ser port re+*este$ /y t&e 'E &as finis&e$.

T&e P*lse#notification information element $oes not contain any specific i$entificationto in$icate w&ic& p*lse &as finis&e$.

It is *n$erstoo$ t&at t&e transmission of t&is information element s&all /e t&e res*lt oft&e last re+*est in a P*lse$#signal information element or in a $igit signal informationelement from t&e 'E asing t&e (N for notification.

Bits Meaning

+ , - . / 0 1 2

1 1 0 0 0 0 0 0 )tet 1

Fig. 10 P*lse#notification information element

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Bits Meaning

+ , - . / 0 1 2

1 0 0 0 0 0 0 0 Impe$ance marer reset

1 0 0 0 0 0 0 1 Impe$ance marer set

1 0 0 0 0 0 1 0 'ow loop impe$ance

1 0 0 0 0 0 1 1 (nomalo*s loop impe$ance

1 0 0 0 0 1 0 0 (nomalo*s line con$ition recei4e$

N)TE> (ll ot&er 4al*es are

reser4e$.

Fig. 11 ,o$ing of parameter line information

T&e p*rpose of t&e 'ine#information information element is to transmit specificinformation on t&e s*/scri/er line stat*s from (N to 'E w&ilst t&ere is no signalingpat&.

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T&e p*rpose of t&e State information element is to in$icate to t&e 'E t&e state of t&e

PSTN signaling protocol entity in t&e (N w&en re+*este$ /y t&e 'E.

Bits Meaning

+ , - . / 0 1 2

1 0 0 1 0 0 0 0 #3t of ser4ice state 5A67: t&is state s&all /e entere$ w&en t&e restartproce$*re &as /een initiate$ /y t&e system management an$ is applica/le to allPSTN ports sim*ltaneo*sly.

1 0 0 1 0 0 0 1 3ll state 5A27: t&e port is inacti4e an$ t&ere is no call in progress. T&is s&all

/e t&e rest state for t&e port interface. W&en t&e PSTN protocol entity in t&e (Nret*rns to t&e N!'' state6 it s&all /e capa/le to $etect an$ report a ?may /ealrea$y present@ s*/scri/er seiA*re.

1 0 0 1 0 0 1 0 *ath initiate% $y A state 5A17: a seiA*re &as /een $etecte$ wit&in t&e (Nan$ an EST(%'IS message &as /een sent to t&e 'E. T&e (N is now waitingfor a EST(%'IS#(, /ac from t&e 'E. In t&e e4ent of no response from t&e'E6 for e:ample in t&e case of an 'E o4erloa$6 t&e EST(%'IS message will /erepeate$ at a low repetition rate ?Timer T1@. ,all collision resol*tion s&all /eac&ie4e$ /y t&e (N an$ 'E $*ring t&is p&ase of t&e call.

1 0 0 1 0 0 1 1 *ath a$ort re83est state 5A07: EST(%'IS message was sent to t&e 'E /*tno EST(%'IS#(, &as yet /een recei4e$. T&e s*/scri/er &as release$ ?e.g.on#&oo@. T&is state s&all /e *se$ to reg*late t&e n*m/er of EST(%'ISmessages t&at may /e sent to t&e possi/ly o4erloa$e$ 'E6 if t&e port is seiAe$

again. (fter a g*ar$ perio$ t&e (N will go /ac to t&e N!'' state.

1 0 0 1 0 1 0 0 Line information state 5A/7: t&is state s&all only /e entere$ into w&ilst a lineinformation from t&e PSTN port is /eing processe$ /y t&e 'E. T&is state mayonly /e entere$ or e:ite$ fromBto t&e N!'' state.

1 0 0 1 0 1 0 1 *ath acti4e 5A.7: t&e acti4e state s&all /e t&e state $*ring w&ic& normalPSTN signalling f*nctions are acti4e for t&at port. 2*ring t&is state a *ser mayprocee$ wit& call esta/lis&ment6 comm*nication or call clearing.

1 0 0 1 0 1 1 0 *ort $loc9e% state 5A-7: t&is state can /e entere$ f rom any state. )nceentere$6 t&e only state t&at t&e port may procee$ to s&all /e t&e N!'' statew&en t&e port is again a4aila/le for ser4ice. )nce t&e /loce$ state &as /eenentere$ all call acti4ity for t&at port s&all /e &alte$ an$ t&e port may /e$eacti4ate$6 e.g. power $own.

1 0 0 1 0 1 1 1 Disconnect re83est state 5A,7: t&e (N re+*ests t&e 'E to $isconnect t&epat&. T&is state s&all /e e:ite$ w&en t&e 'E &as s*ccessf*lly acnowle$ge$ t&e2IS,)NNE,T. If t&is $oes not &appen6 t&e maintenance entity s&all /einforme$.

1 0 0 1 1 1 1 1 reser4e$

Fig. 12 State information element

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T&e p*rpose of t&e (*tonomo*s#signaling#se+*ence information element is to

in$icate to t&e (N6 t&at it &as to start a partic*lar ?pre#$efine$@ signaling se+*encea*tonomo*sly. T&e (*tonomo*s#signaling#se+*ence information element s&all /esent in messages from t&e 'E to t&e (N only. T&e signaling se+*ence to /e starte$s&all /e in$icate$ /y t&e se+*ence type.

Bits Meaning

+ , - . / 0 1 2

1 0 1 0 C C C C Se+*ence type

Fig. 13 (*tonomo*s#signaling#se+*ence information element

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Bits Meaning

+ , - . / 0 1 2

1 0 1 1 C C C C Se+*ence#response type

Fig. 1 Se+*ence#response information element

T&e p*rpose of t&e Se+*ence#response information element is to gi4e a response/ac to t&e 'E a/o*t t&e res*lt of t&e signaling se+*ence. T&e Se+*ence#responseinformation element s&all /e sent in messages from t&e (N to t&e 'E only. T&eSe+*ence#response type in$icates a partic*lar ?pre#$efine$@ response 4al*e. T&eSe+*ence#response type s&all /e co$e$ in /inary.

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Bits Meaning

+ , - . / 0 1 2

0 0 0 0 0 0 0 0 )tet 1

C C C C C C C C 'engt& of Se+*ence#n*m/er content

1 C C C C C C C Se+*ence n*m/er

Fig. 1- Se+*ence#n*m/er information element

T&e p*rpose of t&e Se+*ence#n*m/er information element is to comm*nicate ase+*ence n*m/er to t&e peer entity. T&e Se+*ence#n*m/er information element may

/e sent in /ot& $irections6 from t&e 'E to t&e (N or 4ice#4ersa. T&e Se+*ence#n*m/er information element s&all /e man$atory for SI"N('6 P)T),)'P((METE an$ SI"N(' (, messages an$ is not allowe$ in ot&er messages.T&e lengt& of t&e Se+*ence#n*m/er information element s&all always /e 3 octets. InSI"N(' an$ P)T),)' P((METE messages t&e se+*ence n*m/er containst&e sen$ se+*ence n*m/er M?S@ an$ in SI"N(' (, messages t&e se+*encen*m/er contains t&e recei4e se+*ence n*m/er M?@.

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Bits Meaning

+ , - . / 0 1 2

0 0 0 0 0 0 0 1 )tet 1

C C C C C C C C 'engt& of ,a$ence$#ringing content

1 C C C C C C C ,a$ence$#ringing type

Fig. 1; ,a$ence$#ringing information element

T&e p*rpose of t&e ,a$ence$#ringing information element is to in$icate to t&e (Nt&at ringing wit& a certain pre#$efine$ ca$ence$#ringing type s&all /e starte$ at t&ePSTN *ser port. T&e ca$ence$#ringing type s&all /e co$e$ in /inary. T&e ,a$ence#ringing information element s&all /e sent in messages from t&e 'E to t&e (N only.

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T&e p*rpose of t&e P*lse$#signal information element sent from 'E to (N is to

in$icate to t&e (N t&at a certain p*lse$ signal s&all /e acti4ate$ at t&e PSTN *serport.

T&e $*ration of t&at p*lse$ signal s&all /e in$icate$ /y p*lse $*ration type. T&e p*lse$*ration type points to a pre#$efine$ $escription w&ic& e.g. consists of t&e time fort&e p*lse in total an$ t&e $*ty cycle.

T&e s*ppression in$icator allows t&e 'E to in$icate to t&e (N w&et&er t&e ongoingp*lse$ signal s&all /e s*ppresse$.

T&e acnowle$ge re+*est in$icator allows t&e 'E to re+*est t&at t&e (N notify t&at ap*lse$ signal &as eit&er /eg*n6 en$e$ or one of a se+*ence of p*lses &as en$e$.

T&e N*m/er of p*lses fiel$ contains a n*m/er co$e$ in /inary w&ic& in$icates D&owmany p*lsesD s&all /e sent. T&e 4al*e 0 is in4ali$. T&e lengt& of t&e P*lse$#signalinformation element may 4ary from 3 to - octets.

If t&e P*lse$#signal information element is sent from t&e (N to t&e 'E it correspon$sto a p*lse$ signal at t&e PSTN *ser port generate$ /y t&e s*/scri/ers e+*ipment.

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Bits Meaning+ , - . / 0 1 2

0 0 0 0 0 0 1 0 )tet 1

C C C C C C C C 'engt& of P*lse$#signal content

P*lse type

C 1 1 1 1 1 1 1 P*lse$ normal polar ity

C 1 1 1 1 1 1 0 P*lse$ re4erse$ polarity

C 1 1 1 1 1 0 1 P*lse$ /attery on c#wire

C 1 1 1 1 1 0 0 P*lse$ on &oo

C 1 1 1 1 0 1 1 P*lse$ re$*ce$ /attery

C 1 1 1 1 0 1 0 P*lse$ no /at tery

C 1 1 1 1 0 0 1 Initial ringC 1 1 1 1 0 0 0 Meter p*lse

C 1 1 1 0 1 1 1 -0 A p*lse

C 1 1 1 0 1 1 0 3egister recall ?time$ loop open@

C 1 1 1 0 1 0 1 P*lse$ off &oo ?p*lse$ loop close$@

C 1 1 1 0 1 0 0 P*lse$ /#wire connecte$ to eart&

C 1 1 1 0 0 1 1 Ear t& loop p*lse

C 1 1 1 0 0 1 0 P*lse$ /#wire connecte$ to /attery

C 1 1 1 0 0 0 1 P*lse$ a#wire connecte$ to eart&

C 1 1 1 0 0 0 0 P*lse$ a#wire connecte$ to /attery

C 1 1 0 1 1 1 1 P*lse$ c#wire connecte$ to eart&

C 1 1 0 1 1 1 0 P*lse$ c#wire $isconnecte$C 1 1 0 1 1 0 1 P*lse$ normal /attery

C 1 1 0 1 1 0 0 P*lse$ a#wire $isconnecte$

C 1 1 0 1 0 1 1 P*lse$ /#wire $isconnecte$

0 9 9 C C C C S*ppression in$icator 99 P*lse $*ration type CCCC

00 No s*ppression

01 S*ppression allowe$ /y pre#$efine$7-.1 SI"N(' message from 'E10 S*ppression allowe$ /y pre#$efine$ linesignal from TE11 S*ppression allowe$ /y pre#$efine$7-.1 SI"N(' message from 'E or pre#1 9 9 C C C C C (cnowle$ge re+*est in$ica tor 99 N*m/er of p*lses CCCCC

00 No acnowle$gement re+*este$

01 En$ing acnowle$gement re+*este$w&en finis&e$ eac& p*lse10 En$ing acnowle$gement re+*este$w&en finis&e$ all p*lses11 Start of p*lse acnowle$gement

Fig. 1< P*lse$#signal information element

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T&e p*rpose of t&e Stea$y#signal information element is eit&er to in$icate to t&e (N

t&at a certain stea$y signal s&all /e acti4ate$ at t&e PSTN *ser port ?generate$ /yt&e (N@ or t&at a partic*lar stea$y signal transmitte$ /y t&e s*/scri/ers e+*ipment&as /een $etecte$ at t&e PSTN *ser port w&ic& s&all /e reporte$ to t&e 'E.

Bits Meaning

+ , - . / 0 1 2

0 0 0 0 0 0 1 1 )tet 1

C C C C C C C C 'engt& of Stea$y#signal content

Stea$y#signal type1 0 0 0 0 0 0 0 Normal polarity

1 0 0 0 0 0 0 1 3e4erse$ polarity

1 0 0 0 0 0 1 0 %attery on c#wire

1 0 0 0 0 0 1 1 No /attery on c#wire

1 0 0 0 0 1 0 0 )ff &oo ?loop close$@

1 0 0 0 0 1 0 1 )n &oo ?loop open@

1 0 0 0 0 1 1 0 %attery on a#wire

1 0 0 0 0 1 1 1 (#wire on eart&

1 0 0 0 1 0 0 0 No /attery on a#wire

1 0 0 0 1 0 0 1 No /attery on /#wire1 0 0 0 1 0 1 0 3e$*ce$ /attery

1 0 0 0 1 0 1 1 No /attery

1 0 0 0 1 1 0 0 (lternate re$*ce$ power B no power

1 0 0 0 1 1 0 1 Normal /attery

1 0 0 0 1 1 1 0 Stop ringing

1 0 0 0 1 1 1 1 Start pilot fre+*ency

1 0 0 1 0 0 0 0 Stop pilot fre+*ency

1 0 0 1 0 0 0 1 'ow impe$ance on /#wire

1 0 0 1 0 0 1 0 %#wire connecte$ to eart&

1 0 0 1 0 0 1 1 %#wire $isconnecte$ from eart&

1 0 0 1 0 1 0 0 %attery on /#wire

1 0 0 1 0 1 0 1 'ow loop impe$ance

1 0 0 1 0 1 1 0 ig& loop impe$ance

1 0 0 1 0 1 1 1 (nomalo*s loop impe$ance

1 0 0 1 1 0 0 0 (#wire $isconnecte$ from eart&

1 0 0 1 1 0 0 1 ,#wire on eart&

1 0 0 1 1 0 1 0 ,#wire $isconnecte$ from eart&

Fig. 15 Stea$y#signal information element

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T&e p*rpose of t&e igit#signal information element is eit&er to in$icate to t&e (N t&at

a certain $igit s&all /e sent to t&e s*/scri/ers e+*ipment or t&at a partic*lar $igittransmitte$ /y t&e s*/scri/ers e+*ipment &as /een $etecte$ at t&e PSTN *ser port.

Wit&in t&e $igit information fiel$ t&e n*m/er of p*lses recei4e$ /y (N or re+*ire$ to/e sent /y (N6 co$e$ in /inary6 s&all /e transmitte$. T&e co$e wit& /its 1 to all setto E) is in4ali$. T&e $igit acnowle$ge re+*est in$icator fiel$ allows t&e 'E tore+*est t&e (N to in$icate t&e en$ing of t&e transmission of a $igit to t&e *ser port. Int&e (N to 'E $irection t&is /it s&all always /e set to E).

Bits Meaning

+ , - . / 0 1 2

0 0 0 0 0 1 0 0 )tet 1

C C C C C C C C 'engt& of 2igit#Signal content

1 9 F F C C C C 2igit (cn. 3e+*est In$icator 9 Spare FF 2igit Information CCCC

0 No en$ing acnowle$gementre+*este$

1 En$ing acnowle$gementre+*este$ w&en $igit

transmission is finis&e$

Fig. 1= igit#signal information element

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T&e p*rpose of t&e ecognition#time information element is to in$icate to t&e (N t&at

t&e recognition time of a certain signal &as to /e *p$ate$. T&e ecognition#timeinformation element s&all /e sent in messages from t&e 'E to t&e (N only. In t&eSignal fiel$ all co$ings of signals as specifie$ ?stea$y#signal or p*lse$#signal@ s&all/e 4ali$. T&e $*ration type fiel$ contains an in$e: into a pre#$efine$ ta/le wit&in t&e(N. T&e ta/le s&all contain t&e act*al 4al*e of t&e $*ration of t&e recognition time.T&e act*al 4al*e s&all /e t&e time t&e signal s&all stay acti4e /efore /eingrecogniAe$.

Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 0 0 0 )tet 1

C C C C C C C C 'engt& of 3ecognition#time content

1 C C C C C C C Signal

1 0 C C C C C C 2*ration type

Fig. 20 ecognition#time information element

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T&e p*rpose of t&e Ena/le#a*tonomo*s#acnowle$ge information element is to

in$icate to t&e (N t&at t&ere s&all /e an a*tonomo*s response to a partic*lar linesignal pro$*ce$ /y t&e s*/scri/ers e+*ipment. T&is s&all /e $one to ens*re t&at t&ereaction to t&at signal will /e in time. T&e Ena/le#a*tonomo*s#acnowle$geinformation element s&all /e sent in messages from t&e 'E to t&e (N only. T&elengt& of t&e Ena/le#a*tonomo*s#acnowle$ge information element s&all /e octetsfor stea$y signals or to ; octets for p*lse$ signals.

For t&e Signal fiel$ all co$ings of signals as specifie$ s&all /e 4ali$.

For t&e esponse fiel$ all co$ings of signals as specifie$ s&all /e 4ali$.

In case t&e response is a p*lse$ signal t&e same r*les apply to t&e p*lse $*ration

type6 s*ppression in$icator6 acnowle$ge re+*est in$icator an$ n*m/er of p*lsesfiel$ as specifie$ for t&e P*lse$#signal information element.

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Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 0 0 1 )tet 1

C C C C C C C C 'engt& of Ena/le#a*tonomo*s#acnowle$ge content


1 C C C C C C C esponse

Fig. 21 Ena/le#a*tonomo*s#acnowle$ge information element ?response is a stea$y signal@

Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 0 0 1 )tet 1

C C C C C C C C 'engt& of Ena/le#a*tonomo*s#acnowle$ge content


1 C C C C C C C 3esponse

1 9 9 C C C C C S*ppression in$icator 99 P*lse $*ration type CCCCC

1 9 9 C C C C C (cnowle$ge re+*est

in$icator 99

N*m/er of p*lses CCCCC

Fig. 22 Ena/le#a*tonomo*s#acnowle$ge information element ?response is a p*lse$ signal@

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T&e p*rpose of t&e isa/le#a*tonomo*s#acnowle$ge information element is to

in$icate to t&e (N t&at a pre4io*sly ena/le$ a*tonomo*s acnowle$ge &as to /e$isa/le$. T&e isa/le#a*tonomo*s#acnowle$ge information element s&all /e sent inmessages from t&e 'E to t&e (N only.

Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 0 1 0 )tet 1

C C C C C C C C 'engt& of 2isa/le#a*tonomo*s#acnowle$ge content


Fig. 23 isa/le#a*tonomo*s#acnowle$ge information element

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T&e p*rpose of t&e ,a*se information element is to report to t&e 'E t&e error

con$ition in t&e (N. T&e ,a*se information element s&all /e sent in messages fromt&e (N to t&e 'E only. T&e ,a*se information element for some ca*se types s&allincl*$e a $iagnostic fiel$ in or$er to pro4i$e a$$itional information relate$ to t&eseca*se 4al*es. T&is $iagnostic fiel$ s&all consist of one or two octets6 w&en present6s&all /e a copy of t&e recei4e$ message type i$entifier t&at &as triggere$ t&e sen$ingof t&e message containing t&e ca*se an$6 w&en nee$e$6 t&e rele4ant informationelement i$entifier wit&in t&at message.

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Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 0 1 1 )tet 1

C C C C C C C C 'engt& of ,a*se content

,a*se type

1 0 0 0 0 0 0 0 esponse to ST(T!S EN8!I9

1 0 0 0 0 0 0 1 Protocol $iscriminator error

1 0 0 0 0 0 1 1 '3 a$$ress error

1 0 0 0 0 1 0 0 Message type *nrecogniAe$

1 0 0 0 0 1 0 1 )*t of se+*ence information element

1 0 0 0 0 1 1 0 epeate$ optional information element

1 0 0 0 0 1 1 1 Man$atory information element missing

1 0 0 0 1 0 0 0 !nrecogniAe$ information element

1 0 0 0 1 0 0 1 Man$atory information element content error1 0 0 0 1 0 1 0 )ptional information element content error

1 0 0 0 1 0 1 1 Message not compati/le wit& pat& state

1 0 0 0 1 1 0 0 epeate$ man$atory information element

1 0 0 0 1 1 0 1 Too many information elements

0 C C C C C C C 2iagnostic ?message type i$entifier@

C C C C C C C C 2iagnostic ?information element i$entifier@

Fig. 2 ,a*se information element

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T&e p*rpose of t&e eso*rce#*na4aila/le information element is to in$icate to t&e 'E

t&at t&e partic*lar reso*rce w&ic& &a$ /een re+*este$ /y t&at information elementcopie$ into t&e ret*rne$ eso*rce#*na4aila/le information element is not a4aila/le.

T&e eso*rce#*na4aila/le information element s&all /e sent in SI"N(' messagesfrom t&e (N to t&e 'E only. T&e lengt& of t&e eso*rce#*na4aila/le informationelement $epen$s on t&e lengt& of t&e information element ret*rne$. T&erefore it may4ary /etween 3 an$ 5 octets. T&e copy fiel$ contains t&e copy of t&at informationelement for w&ic& t&e re+*este$ action co*l$ not /e performe$ $*e to t&e*na4aila/ility of reso*rces.

Bits Meaning

+ , - . / 0 1 2

0 0 0 1 0 1 0 0 )tet 1

C C C C C C C C 'engt& of reso*rce *na4aila/le content

,opy of information element wit& faile$ re+*est

Fig. 2- eso*rce#*na4aila/le information element

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3 PSTN Protocol Message Flow

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3.1 Message Flows for V.1

3.1.1 Message Flows for !ial P"lse S"#scri#ers

(N

2ial p*lse$igits

off#&oo

(#si$e'E

Esta/lis&

?Stea$y#off#&oo@

(N

Esta/lis& (cnowle$ge

Signal

?2igit Signal@

Signal

?2igit Signal@

Signal

?2igit Signal@

Signal (cnowle$ge

Signal (cnowle$e

Signal

?2igit Signal@

Signal

?Stea$y on#&oo@

on#&oo

on#&oo

off#&oo

Esta/lis&

?,a$ence inging@


Signal

?Stea$y off#&oo@

Signal

?Stea$y on#&oo@

2isconnect

2isconnect ,omplete

2isconnect

2isconnect ,omplete

Fig. 2; Message flows for $ial p*lse s*/scri/ers ?o4er4iew@

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3.1.2 Message Flows for !TMF S"#scri#ers

(N

off#&oo

2TMF

$igits

off#&oo

%#si$e

(#si$e(N


Signal (cnowle$ge

Esta/lis&?,a$ence 3inging@

Signal

?Stea$y on#&oo@

Signal

?Stea$y off#&oo@

Esta/lis&

?Stea$y#off#&oo@


Signal

?Stea$y on#&oo@

2isconnect

2isconnect ,omplete2isconnect

2isconnect ,omplete

on#&oo

on#&oo

'E

Fig. 2< Message flows for TMF s*/scri/ers ?o4er4iew@

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3.2 Message Flows for V.2

(#(N 'E %#(N

EST(%'IS?off oo@

EST(%'IS

(,

(''),(TI)N

,)MP'ETE

(''),(TI)N

P)T),)'P((METE

2ial tone

SI"N('

SI"N('G(,

SI"N('G(,

SI"N('

SI"N('?(nswer@

(''),(TI)N,)MP'ETE

(''),(TI)N

EST(%'IS?,(2. inging@

EST(%'IS

(,

(22ESSG,)MP'ETE

ing tone

SI"N(' ?off &oo@

SI"N(' ?on &oo@

2E(''),(TI)N

2E(''),(TI)NG,)MP'ETE

2IS,)NNE,T

2IS,)NNE,TG,)MP'ETE

Fig. 25 PSTN call set*p

03 tw2104eu01 eg0001 pstn protocol

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