1、 21-10 Page 1 E Recommendation T/STI 21-10 (Odense 1986) CALL HANDLING SEQUENCES FOR THREE PARTY SERVICE Recommendation proposed by Working Group T/WG 11 “Signalling Systems and Telephone Networks/ISDN” (STI) Text of the Recommendation adopted by the “Telecoiimiiiiicatioiis” Commissioii: “The Europe
2、an Conference of Postal and Telecommunications Administration, considering - that the supplementary services which imply Three Party Service are subject to harmonisation, - that the operational requirements for such supplementary services are defined in the “Handbook on services and - that the opera
3、tion of this service requires the utilization of “additional signalling feature” as defined in Recom- - that an appropriate way of specifying additional signalling information and its flow is by means of call handling - that the definition of a standardized Three Party Service (TPS) call handling se
4、quence is usefull, especially in the facilities offered to the subscribers in modern telephone systems” prepared by Working Group SF i, mendation T/CS 20-26 2, sequence charts, according to Recommendation T/CS 21-01 3, case where the TPS will be provided accross borders, recoinmends that member admi
5、nistrations adopt for the provision of the supplementary service “Three Party Service” (TPS) the call handling sequences as outlined in this Recommendation.” 1. 2. 2.1. 2.2. 2.3. INTRODUCTION This Recommendation specifies the call handling sequences for the supplementary service “Three Party Service
6、” (TPS). The different possible requirements of the service are defined in the SF Handbook in Family 11.1 i: 1 1.1.1. Hold for enquiry. 11.1.2. 11.1.3. 11.1.4. Full. Hold for enquiry with three-way conversation. Hold for enquiry with transfer. OPTIONS OF THE SERVICE From the technical point of view,
7、 the Three Party Service can be split up into the following 3 different options : - hold for enquiry; - three-way conversation; - transfer. The “full three party service” has all 3 options combined. The “three-way conversation” option as well as the “transfer” option can be applied only in conjuncti
8、on with the “hold for enquiry” option. In the sequence chart the following two different options of the TPS Family liave been described: - hold for enquiry; - three have way conversation. The option “transfer” is left for further study. Edition of September 15, 1986 -_ CEPT T/STI*ZL-10 E Bb m 232b4L
9、4 00061559 9 m T/STI 21 -1 O E Page 2 3. PROVISION OF THE SERVICE The TPS can be provided for all types of subscriber lines (including lines to PABXs) which have the required signalling capability. It should be possible to have the TPS and the call waiting service provided at the same time. Compatib
10、ility with other supplementary services is left for further study. 4. DEFINITION OF THE TERM “TWO CALL MODE” In the following text and chart the term “two call mode” is used. A subscribers equipment is in the two call mode immediately after the subscriber has issued a hold request order until one of
11、 the two calls or the call attempt respectively has been cleared. 5. TECHNICAL REQUIREMENTS -No audible indication is given by the network to a subscriber who is being held. However, if the supporting signalling system allows, a signalling type of indication about the change from the held state to t
12、he active state or from the active state to the held state respectively may be given. - Call waiting is suspended for the initiating subscriber of TPS during the two call mode. - A subscriber having answered an enquiry call must not enter the two call mode, e.g. by TPS or call - A subscriber involve
13、d in an enquiry call should not be allowed to initiate an enquiry call by himself (see - Both subscribers of an original call may enter the two call-mode, either by TPS or call waiting. - A subscriber of an original call may enter the two call mode, either by TPS or call waiting. - A subscriber who
14、clears although he is holding another subscriber may be rerung. - The establishment of a Three Way Conversation is limited to one side of the original call at a time. - When the two call mode ends, the remaining call is to be considered as a normal call. From these technical requirements the state t
15、ransition table given in the following chapter as seen from subscriber A is derived. ”waiting. however note 3 in 0 7.3.). 6. STATE TRANSITION TABLE The state transition table presents the possible actions a subscriber may initiate within the Three Party Service, the possible states after execution o
16、f these actions and the possible transitions taking into account the above mentioned restrictions. 6.1. Possible actions (X denotes a subscriber) 1. X wants to have an enquiry Cali. 2. X wants to switch over from the active connection to the held connection. 3. X wants to have a Three Way Conversati
17、on. 4. X wants to release the held connection and wants to continue on the active connection (this action may not be provided for voice calls). 5. X wants to release the active connection and wants to continue on the held connection. 6. X wants to discontinue the Three Way Conversation, wants to hol
18、d one connection and keep the other connection active. 7. X wants to disconnect altogether. 6.2. Possible states O. all subscribers idle I. simple connection a) A connected with B O O b) A connected with C c) B connected with D Edition of September 15, 1986 a T/STI 21 -10 E Page 3 II. main connectio
19、n hold, enquiry connection active a) A holds B o-1-0 A connected with C b) B holds A O B connected with D III. main connection active, enquiry connection held a) A connected with B O O b) B connected with A A holds C I I I B holds D O IV. three way conversation O O I o States O to IV are the basic s
20、tates as conceived by subscribes A. With the exception of the three way conversation state subscriber B is from a technical point of view not aware of the state of subscriber A, therefore subscriber B may initiate successfully at any time all possible actions as described above except action 3. This
21、 leads to the following additional states. V. main connection held by either side, both enquiry connections active A holds B o-/-o A connected with C B holds A O O Il B connected with D main connection held by one side, one enquiry call active and one enquiry held VI. a) B holds A 0-1-0 I B connecte
22、d with D i I A is held by B O A holds C b) A holds B A connected to C B is held by A B holds D O b) B connected with A and D A holds B A connected to C Edition of September 15, 1986 VII. three way conversation, main connecllm is held, call active a) A connected with B and C 0-1-0 Ir I B holds A B co
23、nnected with D O O CEPT T/STI*2L-LO E b E 232cS4L4 0009561 7 T/STI 21 -1 O E Page 4 VIII. main connection active, two enquiry connections held A connected with B O O I I A holds C l I I I B connected with A .o O B holds D three way conversation, one enquiry connection held a) A connected with B and
24、C O O IX. ir I B holds D b) B connected with A and D O A holds C 6.3. Possible transitions (A capital letter denotes a subscriber.) (A figure denotes an action.) (A Roman figure denotes a state.) from I Al -+ IIa A2- A3 - A4 - A5 - A6 - A7 -+ O from II Al - B1 -+ V A2 -+ IIIa B2 - A3 -+ IVa B3 - A4
25、-+ Ib B4 - A5 -+ Ia B5 - A6 - B6 - A7 -+ O B7 -+ Ib from III Al - B1 -+ VIa A2 -+ IIa B2 - A3 -+ IVa B3 - A4 -+ Ia B4 - A5 -+ Ib B5 - A6 - B6 - A7 -+ O B7 -+ Ib from IV Al - B1 -+ VIIa A2 - B2 - A3 - B3 - A4 - B4 - A5 - B5 - A6 -+ IIIa/IIa B6 - A7 -+ O B7 -+ Ib A2 -+ VIa B2 -+ VIb A3 -+ VIIa B3 -+ V
26、IIb A4 -+ Ib+Ic B4 -+ Ib+Ic A5 -+ IIb aB5 -+ IIa A7 -+ IC B7 -+ Ib fromV Al - B1 - A6 - B6 - c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ Ia c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ Ia c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ Ia c1 - DI - c2 - D2 - c3 - D3 - c4 - D4 - c5 - D5 - C6 - D6 - C7 -+ IIb D7 -+ IIa Edition of
27、 September 15, 1986 7. 7.1. 7.1.1. O 7.1.2. 7.1.3. O CEPT T/STI*ZL-LO E 86 m 23261134 fromVI Al - A2 -+ V A3 -+ VIIa A4 -+ IIb A5 -+ Ib+Ic A7 -+ IC from VI1 Al - A6 - A2 - A3 - A4 - A5 - A6 -+ VpIa A7 -+ IC from VI11 Al - A2 -+ VIb A3 -+ Ea A4 -+ IIIb A5 -+ Ib+Ic A7 -+ IC from M Al - A2- A3 - A4 - A
28、5 - A6 - BI - B2 -+ VIIIa B3 + IXb B4 -* Ib+Ic B5 -+ IIIa B7 -+ Ib B2 -+ IXa B4 -+ Ib+Ic B5 -* Na B7 -+ Ib B6 - B1 - B3 - B6 - B1 - B2 -+ VIa B3 -+ IXb B4 -+ IIIa B5 -+ Ib+Ic B7 -+ Ib B2 -+ VIIa B4 -+ IVa B5 -* Ib+Ic B6 - B1 - B3 - A6 -+ VIIIa/VIb B6 - A7 -+ IC B7 + Ib 0009562 9 m T/STI 21 -1 O E Pa
29、ge 5 c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ IIb c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ IIb c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ IIIb c1 - c2 - c3 - c4 - c5 - C6 - C7 -+ IIIb D1 - D2 - D3 - D4 - D5 - D6 - D7 3 IIIa D1 - D2 - D3 - D4 - D5 - D6 - D7 -* IVa D1 - D2 - D3 - D4 - D5 - D6 - D7 -+ IIIa D1 - D2 - D3
30、 - D4 - D5 - D6 - D7 -+ IVa CALL HANDLING SEQUENCE CHART The service instructions (SI) according to Recommendation T/CS 20-26 2 required for operation of TPS are listed below. The SIs transmitted on the subscriber lines are listed in Q 7.1. The SIs on interexchange signalling links are listed in Q 7
31、.2. The SIs on interexchange signalling links are of interest in the originating and destination exchanges only and need not be interpreted by intermediate exchanges. Service insructions on the subscriber lines Service iristructions received by the public excharige - three way conversation request;
32、- discontinue three way conversation; - enquiry call request. Service iiistructions seiit from the public exchaiige - hold indication; - active indication; - hold refused; - normal call indication; - enquiry call request accepted; - three way conversation request accepted. Procedures at the user-net
33、work iriteiface - reject and switch procedure; - reject held call procedure; - hold and switch procedure. Edition of September 15, 1986 CEPT T/STI*E!L-LO E 6 W 2326434 0009563 O W T/STI 21 -1 O E Page 6 7.2. 7.2.1. 7.2.2. 7.3. Service instructions beween originating and destination exchange Forward
34、disection only - normal call set-up procedure with SI “enquiry call”; - change enquiry call to normal call. Forward and backward disection - “you are held”; - “you are active”; - three way conversation request; - three way conversation possible; - three way conversation impossible. Notes 1. In case
35、of interworking between an enhanced and an unenhanced signalling system the decision on 2. In case of an ISDN user-network access interface the address information for the enquiry call may be 3. An administration may decide not to apply SI, enquiry call, throughout its network. 4. In case that the h
36、eld call is the enquiry call the RNRs 2030, 2040 and 2050 do not apply. 5. In case that the rejected call is the original call the RNRs 2030, 2040 and 2050 should be applied additionally. 6. An administration may exceptionally decide not to apply this service instruction throughout its network. This
37、, however, can cause undesirable consequences for other administrations in the case that the subscribers envolved belong to different administrations. sending the interexchange signal is taken by exchange A. sent together with the enquiry call request. Edition of September 15, 1986 - WR - 10 20 30 4
38、0 50 60 - 100 110 120 130 END 200 21c - 22c ENE - CEPT T/STI*ZL-LO E 6 W 2326414 0009564 2 W T/STI 21 -1 O E Page 7 Exchange A Exchange B Exchange C Three Party Service: Hold for Enquiry. Three W Conversation I Start of sequence Normal call set-up procedure Call in progress with sub. B If sub. A wan
39、ts to make an :nquiry call, see RNR 300 If sub. A wants to clear see RNR 100 Ail other requests from sub. A concerning Three Party Service are ignored, continue at RNR 30 Continuation from RNR 50. Si Clear . Normal cle Call in progress with sub. A If sub. B wants to do anything concerning Three Part
40、y Service then assume sub. B to be sub. A and sub. A to be sub. B and continue at RNR 30 If sub. B wnats to clear, see RNR 200 I. A wants to clear a normal call : procedure Sub. A is cleared r Sub. B is cleared END OF SEQUENCE I I Continuation from RNR 50. Sub. B wants to clear a normal call Normal
41、clear procedure Clear 4 t- Sub. A is cleared Sub. B is cleared END OF SEQUENCE Edition of September 15, 1986 CEPT T/STI*21-10 E b W 2326434 0009565 4 W T/STI 21 -1 O E Page 8 RNR 300 310 315 320 325 330 340 360 370 380 390 400 410 420 440 Exchange A Continuation from RNR 40. Sub. A wants to make an
42、enquiry call Enquiry call seques t - If enquiry call is possible, conti- nue at RNR 330 Enquiry call refused - Continue at RNR 30 Set two call mode indicator for sub. A Exchange B Hold SI “you are held” indication b. Enquiry call request accepted , Normal call set-up procedure with SI “enquiry call”
43、 Exchange C b If sub. A gives insufficient dial- ling information within time TI, continue at RNR 620 If network is congested or sub. C is busy, continue at RNR 600 I I Call arrival Call arrival confismation Call arrived indication .4 _c_, If sub. A wants to clear his call request to sub. C before s
44、ub. C answers, see RNR 800 If time supervision on answer T2 expires, continue at RNR 620 Answer confirmation Call answered Set enquiry call indicator for sub. C Answer response Continuation at RNR i200 I I a Edition of September 15, 1986 CEPT T/STI*21-10 E b 2326414 00095bb b W Exchange A - RNR 600
45、- 610 620 630 640 650 660 670 700 710 720 730 740 750 76C - Exchange B Exchange C T/STI 21 -1 O E Page 9 Call in progress with sub. B Call in progress with sub. A I Unsuccessful call 7 I I Unsuccessful call Normal clear procedure Reset two call mode indicator for sub. A If sub. A clears, see RNR 700
46、 Continuation from RNR 640. Sub. A clears whilst holding another sub. Clear . If re-ringing is not applied, con- tinue at RNR 120 Call arrival indication - If time supervision on answer T, expires, continue at RNR 120 Off hook SI “you are active” Active indication . bh I Continue as for a normal cal
47、l at RNR 30 Edition of September 15, 1986 CEPT T/STI*21-LO E 6 W 2326434 0009567 47 T/STI 21 -1 O E Page 10 RNR 800 - 810 820 830 835 840 850 900 910 - 920 930 Exchange A Exchange B Continuation from RNR 400. Sub. A clears enquiry call attempt before answer If sub. A clears altogether, con- tinue at
48、 RNR 900 Reject and switch procedure Normal clear procedure Reset two call mode indicator for sub. A Active SI “you are active” indication bh Call in progress with sub. B Call in progress with sub. A Continuation as for a normal call at RNR 30 Exchange C - Sub. C is cleared Continuation from RNR 810
49、. Sub. A clears enquiry call attempt before answer Clear Normal clear procedure . b Reset two call mode indicator for sub. A Sub. C is cleared Continuation at RNR 720 Edition of September 15, i386 RNR 1200 1210 1220 1230 1240 1250 1260 - TISTI 21 -1 O E Page 11 Exchange A I ExchangeB I ExchangeC Continuation from RNR 440, 1260, 1400, 1600, 1930,2320,2640,2920. Sub. A has sub. B and hold and the call to sub. C active (if sub. A has the call to sub. B active and the call to sub. C on hold the same sequences should be-fc If sub. A wants to switch over from th
