ETSI EN 300 392-11-21 V1.1.1 (2003-04)

Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary services stage 2; Sub-part 21: Ambience Listening (AL)

DEN/TETRA-03001-11-21

Prizemni snopovni radio (TETRA) - Govor in podatki (V+D) - 11. del: Dopolnilne storitve stopnje 2 - 10.-21. del: Poslušanje okolice (AL)

General Information

• Status: Published
• Publication Date: 07-Apr-2003
• Technical Committee: TCCE 3 - TCCE Air Interface and Network Protocols
• Current Stage: 12 - Completion
• Due Date: 11-Apr-2003
• Completion Date: 08-Apr-2003
• Mandate: BC-T-344
• Ref Project: SIST EN 300 392-11-21 V1.1.1:2003 - Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary services stage 2; Sub-part 21: Ambience Listening (AL)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 300 392-11-21
01-MXOLM
Prizemni snopovni radio (TETRA) - Govor in podatki (V+D) - 11. del: Dopolnilne
storitve stopnje 2 - 10.-21. del: Poslušanje okolice (AL)
Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary
services stage 2; Sub-part 21: Ambience Listening (AL)
Ta slovenski standard je istoveten z: EN 300 392-11-21 (
ICS:
33.070.10 Prizemni snopovni radio Terrestrial Trunked Radio
(TETRA) (TETRA)
SIST EN 300 392-11-21 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 300 392-11-21 V1.1.1:2003

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SIST EN 300 392-11-21 V1.1.1:2003
DRAFT
EUROPEAN pr ETS 300 392-11-21
TELECOMMUNICATION September 1996
STANDARD
Source: ETSI TC-RES Reference: DE/RES-06001-11-21
ICS: 33.060, 33.060.50
Key words: TETRA, V+D, SS, AL
Radio Equipment and Systems (RES);
Trans-European Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 11: Supplementary Services (SS) Stage 2;
Part 11-21: Ambience Listening (AL)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
Tel.: [phone] - Fax: [phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1996. All rights reserved.

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SIST EN 300 392-11-21 V1.1.1:2003
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Draft prETS 300 392-11-21: September 1996
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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SIST EN 300 392-11-21 V1.1.1:2003
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Draft prETS 300 392-11-21: September 1996
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
4 Supplementary Service Ambience Listening (SS-AL) Stage 2 specification.8
4.1 Functional model.8
4.1.1 Functional model description.8
4.1.2 Description of FEs.9
4.1.2.1 Served user's agent functional entity, FE1 .9
4.1.2.2 AL control functional entity, FE2 .9
4.1.2.3 Affected user's agent functional entity, FE3 .10
4.1.2.4 Generic functional control entity, FE4.10
4.1.2.5 Second listening party's agent functional entity, FE5 .10
4.2 Information flows.10
4.2.1 Definition of information flows .10
4.2.1.1 Interrogation.10
4.2.1.1.1 INTERROGATE-REQUEST .11
4.2.1.1.2 INTERROGATE-RESULT .11
4.2.1.2 Invocation .11
4.2.1.2.1 INVOKE-REQUEST1.11
4.2.1.2.2 INVOKE-REQUEST2.11
4.2.1.2.3 INVOKE .12
4.2.1.2.4 INVOKE-ACK.12
4.2.1.2.5 INVOKE-RESULT.12
4.2.1.3 Information.13
4.2.1.3.1 INFORMATION.13
4.2.2 Relationship of information flows to basic call information flows.13
4.2.3 Information flow sequences .13
4.2.3.1 Interrogation.14
4.2.3.2 Normal Interrogation of AL when FE1 in visited system.14
4.2.3.3 Invocation with served user, affected user and second
listening party in home system .14
4.2.3.4 Invocation with served and affected user in home system.15
4.2.3.5 Invocation with served and affected user in home system
with a 2nd listening party .16
4.2.3.6 Invocation with second Listening Party, served user in
visited system .17
4.2.3.7 Invocation with served user in visited system, no second
listening party.17
4.2.3.8 Invocation with affected user in visited system, with
second listening party .18
4.2.3.9 Invocation with affected user in visited system, no second
listening party.18
4.2.3.10 AL call cleardown, with affected user in visited system,
due to a new incoming call .19
4.2.4 FE Actions .19
4.2.4.1 Functional entity actions of FE1.19
4.2.4.2 Functional entity actions of FE2.20
4.2.4.3 Functional entity actions of FE3.20
4.2.4.4 Functional entity actions of FE4.20
4.2.4.5 Functional entity actions of FE5.21

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4.3 Allocation of FEs to physical equipment. 21
4.4 Inter-working considerations . 21
History. 22

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SIST EN 300 392-11-21 V1.1.1:2003
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Draft prETS 300 392-11-21: September 1996
Foreword
This draft European Telecommunication Standard (ETS) has been produced by the Radio Equipment and
Systems (RES) Technical Committee of the European Telecommunications Standards Institute (ETSI),
and is now submitted for the Public Enquiry phase of the ETSI standards approval procedure.
This ETS is a multi-part standard and will consist of the following parts:
Part 1: "General network design".
Part 2: "Air Interface (AI)".
Part 3: "Inter-working", (DE/RES-06001-3).
Part 4: "Gateways", (DE/RES-06001-4).
Part 5: "Terminal equipment interface", (DE/RES-06001-5).
Part 6: "Line connected stations", (DE/RES-06001-6).
Part 7: "Security".
Part 8: "Management services", (DE/RES-06001-8).
Part 9: "Performance objectives", (DE/RES-06001-9).
Part 10: "Supplementary Services (SS) Stage 1".
Part 11: "Supplementary Services (SS) Stage 2".
Part 12: "Supplementary Services (SS) Stage 3".
Part 13: "SDL Model of the Air Interface".
Part 14: "PICS Proforma", (DE/RES-06001-14).
Part 15: "Inter-working - Extended Operations", (DE/RES-06001-15).
Proposed transposition dates
Date of latest announcement of this ETS (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 6 months after doa

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SIST EN 300 392-11-21 V1.1.1:2003
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Draft prETS 300 392-11-21: September 1996
1 Scope
This European Telecommunication Standard (ETS) defines the stage 2 specification of the
Supplementary Service Ambience Listening (SS-AL) for the Trans-European Trunked Radio (TETRA) as
provided by European operators. Stage 2 identifies the functional entities involved in the supplementary
service and the information flows between them.
Charging principles and Man-Machine Interface (MMI) are outside the scope of this ETS.
The SS-AL enables a served user to place a TETRA Mobile Station (MS) or Line Station (LS) into a
special type of voice call teleservice whereby the called MS (or LS) transmits without any action from, or
indication to, the affected user. The teleservice may include a second listening party.
2 Normative references
This ETS incorporates, by dated or undated reference, provisions from other publications.
These†normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to, or revisions of, any of these publications
apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest
edition of the publication referred to applies.
[1] CCITT Recommendation I.130 (1988): "Method for the characterization of
telecommunication services supported by an ISDN and network capabilities of
an ISDN".
[2] ETS 300 392-2: "Radio Equipment and Systems (RES); Trans-European
Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI)".
[3] ETS 300 392-1: "Radio Equipment and Systems (RES); Trans-European
Trunked Radio (TETRA); Voice plus Data (V+D); Part 1: General Network
Design".
[4] ITU-T Recommendation Z.100 (1993): "Specification and Description Language
(SDL)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
AL call: A call in which ambience listening functionality is requested. During the AL call, the affected
user's MS (or LS) transmits without any action from, or indication to, the affected user.
affected user: The user who is subject to the operation.
served user: The user who is invoking this supplementary service.
second listening party: A TETRA individual or group which may listen into the AL call.

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Draft prETS 300 392-11-21: September 1996
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AL Ambience Listening
CC Call Control
CCA Call Control (functional entity Agent)
FE Functional Entity
GTSI Group TETRA Subscriber Identity
ISDN Integrated Services Digital Network
ITSI Individual TETRA Subscriber Identity
LS Line Station
MS Mobile Station
SDL (Functional) Specification and Description Language
SS Supplementary Service
NOTE: The abbreviation SS is only used when referring to a specific supplementary service.
SwMI Switching and Management Infrastructure
TETRA Trans-European Trunked Radio
4 Supplementary Service Ambience Listening (SS-AL) Stage 2 specification
4.1 Functional model
4.1.1 Functional model description
The functional model shall comprise the following Functional Entities (FEs):
- FE1 served user's service agent;
- FE2 ambience listening control entity in the served user's home system;
- FE3 affected user's service agent;
- FE4 generic functional control entity in a visited system with respect to the served user;
- FE5 second listening party's service agent.
The following relationships shall exist between these FEs:
- ra between FE1 and FE2;
- rb between FE2 and FE3;
- rc between FE2 and FE4 in different systems;
- rd between FE4 and FE1;
- re between FE4 and FE3;
- rf between FE5 and FE2;
- rg between FE5 and FE4.
Figure 1 shows these FEs and their relationships.

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Draft prETS 300 392-11-21: September 1996
Second Listening Party
SYSTEM 1
FE5
CCA
rf
Affected User
Served User
FE1 ra FE2 FE3
rb
CC
CCA
CCA
ISI
rc
SYSTEM 2
Served User Affected User
rd
FE3
FE4
FE1
re
CC CCA
CCA
Second Listening Party
FE5
rg
CCA
Figure 1: Operational and management functional model for SS-AL
4.1.2 Description of FEs
4.1.2.1 Served user's agent functional entity, FE1
The function entity FE1 shall: receive interrogation and invocation information from the served user and
information (positive or negative acknowledgements) about the executed service request from FE2 in
order to deliver it to the served user.
4.1.2.2 AL control functional entity, FE2
The functional entity FE2 shall:
- perform checks, give instructions and perform actions for the data received for interrogation and
invocation;
- construct and deliver the PDUs;
- provide the affected user's application with applicable SS-AL data by sending it to the affected
user's service agent FE3 via FE4 if the affected user is located in a different system;
- provide the served user's agent functional entity with the positive or negative acknowledgement of
the requested service. This is sent to FE4 if the served user is in visited system;
- given that a second listening party is involved in the AL call, provide the second listening party's
application with applicable SS-AL data by sending it to the second listening party's service agent
FE5 via FE4 if the second listening party is located in a different system;
- if any exception conditions are noticed by SwMI, FE2 stops the execution of the service request and
the AL call will be cleared down;
- clear down the AL call if a new incoming call is received for the affected user.

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Draft prETS 300 392-11-21: September 1996
4.1.2.3 Affected user's agent functional entity, FE3
The functional entity FE3 shall:
- receive information of the new AL invocation.;
- disable user notification of the call with which AL is invoked.
The functional entity FE3 may:
- clear down the AL call if the affected user attempts to make a new call, normal call disconnection
procedures shall apply to the AL call, as specified in ETS 300 392-2 [2];
- when the AL call ends FE3 reverts to normal operation;
- in one SS-AL invocation there may only be one affected user.
4.1.2.4 Generic functional control entity, FE4
The functional entity FE4 shall:
- clear down the AL call if a new incoming call is received for the affected user;
- receive information flows from the ambience listening control functional entity, the served user's
control functional entity and the affected user's control functional entity.
The information flows FE4 shall be able to receive:
- acknowledgements sent by an affected user located in its system;
- requests and responses sent by ambience listening control entity in SS-AL home system;
- requests sent by a served user located in its system.
FE4 adds the applicable addressing information to the information flows and they are sent to their
recipient:
- the affected user that is currently in this system for SS-AL invocation;
- the SS-AL control entity for the responses sent by the affected user;
- the served user that is currently in this system for SS-AL interrogation and invocation;
- the second listening party that is currently in this system for SS-AL information.
4.1.2.5 Second listening party's agent functional entity, FE5
The functional entity FE5 shall: receive an information flow for the new AL call set-up.
4.2 Information flows
4.2.1 Definition of information flows
In the tables listing the element type indicates whether the data type is Mandatory (M) or optional (O).
4.2.1.1 Interrogation

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Draft prETS 300 392-11-21: September 1996
4.2.1.1.1 INTERROGATE-REQUEST
This shall be an information flow for the routes ra, rc and rd from FE1 to FE2. The flow shall be sent to
FE2 via FE4 if FE1 is in a visited system. The flow is used to interrogate the SS-AL for a specified
individual, a list of individuals or a range of individuals. Table 1 lists the elements within the
INTERROGATE-REQUEST information flow.
Table 1: Content of INTERROGATE-REQUEST
Element Type Value Remarks
Interrogated Subscribers Identity(s) M This may be a single identity, If range is given, the first and
a list or a range of identities the last value is given
4.2.1.1.2 INTERROGATE-RESULT
This shall be an information flow for the routes ra, rc and rd from FE2 to FE1. The flow shall be sent to
FE1 via FE4 if FE1 is in a visited system. The flow shall be used to acknowledge an interrogation request
for a specified individual, a list of individuals or a range of individuals. Table 2 lists the elements within the
INTERROGATE-RESULT information flow.
Table 2: Content of INTERROGATE-RESULT
Element Type Value Remarks
Interrogated Subscribers Identity(s) M This may be a single identity, If range is given, the first and
a list or a range of identities the last value is given
Result M invoked, Indicates if the interrogation
service not defined for the was successful. This value
TETRA id., applies to all identities given
rejected for any reason, in the field 'Interrogated
user not authorized, Subscriber Identity(s)' above
unknown TETRA identity,
parameters not valid or
insufficient information
4.2.
...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Prizemni snopovni radio (TETRA) - Govor in podatki (V+D) - 11. del: Dopolnilne storitve stopnje 2 - 10.-21. del: Poslušanje okolice (AL)Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary services stage 2; Sub-part 21: Ambience Listening (AL)33.070.10Prizemni snopovni radio (TETRA)Terrestrial Trunked Radio (TETRA)ICS:Ta slovenski standard je istoveten z:EN 300 392-11-21 (3SIST EN 300 392-11-21en01-PDM3SIST EN 300 392-11-21SLOVENSKI
STANDARD



SIST EN 300 392-11-21 V1.1.1:2003



DRAFTEUROPEANprETS 300 392-11-21TELECOMMUNICATIONSeptember 1996STANDARDSource: ETSI TC-RESReference: DE/RES-06001-11-21ICS:33.060, 33.060.50Key words:TETRA, V+D, SS, ALRadio Equipment and Systems (RES);Trans-European Trunked Radio (TETRA);Voice plus Data (V+D);Part 11: Supplementary Services (SS) Stage 2;Part 11-21: Ambience Listening (AL)ETSIEuropean Telecommunications Standards InstituteETSI SecretariatPostal address: F-06921 Sophia Antipolis CEDEX - FRANCEOffice address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCEX.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail].: [phone] - Fax: [phone]Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and theforegoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1996. All rights reserved.SIST EN 300 392-11-21 V1.1.1:2003



Page 2Draft prETS 300 392-11-21: September 1996Whilst every care has been taken in the preparation and publication of this document, errors in content,typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to"ETSI Editing and Committee Support Dept." at the address shown on the title page.SIST EN 300 392-11-21 V1.1.1:2003



Page 3Draft prETS 300 392-11-21: September 1996ContentsForeword.51Scope.72Normative references.73Definitions and abbreviations.73.1Definitions.73.2Abbreviations.84Supplementary Service Ambience Listening (SS-AL) Stage 2 specification.84.1Functional model.84.1.1Functional model description.84.1.2Description of FEs.94.1.2.1Served user's agent functional entity, FE1.94.1.2.2AL control functional entity, FE2.94.1.2.3Affected user's agent functional entity, FE3.104.1.2.4Generic functional control entity, FE4.104.1.2.5Second listening party's agent functional entity, FE5.104.2Information flows.104.2.1Definition of information flows.104.2.1.1Interrogation.104.2.1.1.1INTERROGATE-REQUEST.114.2.1.1.2INTERROGATE-RESULT.114.2.1.2Invocation.114.2.1.2.1INVOKE-REQUEST1.114.2.1.2.2INVOKE-REQUEST2.114.2.1.2.3INVOKE.124.2.1.2.4INVOKE-ACK.124.2.1.2.5INVOKE-RESULT.124.2.1.3Information.134.2.1.3.1INFORMATION.134.2.2Relationship of information flows to basic call information flows.134.2.3Information flow sequences.134.2.3.1Interrogation.144.2.3.2Normal Interrogation of AL when FE1 in visited system.144.2.3.3Invocation with served user, affected user and secondlistening party in home system.144.2.3.4Invocation with served and affected user in home system.154.2.3.5Invocation with served and affected user in home systemwith a 2nd listening party.164.2.3.6Invocation with second Listening Party, served user invisited system.174.2.3.7Invocation with served user in visited system, no secondlistening party.174.2.3.8Invocation with affected user in visited system, withsecond listening party.184.2.3.9Invocation with affected user in visited system, no secondlistening party.184.2.3.10AL call cleardown, with affected user in visited system,due to a new incoming call.194.2.4FE Actions.194.2.4.1Functional entity actions of FE1.194.2.4.2Functional entity actions of FE2.204.2.4.3Functional entity actions of FE3.204.2.4.4Functional entity actions of FE4.204.2.4.5Functional entity actions of FE5.21SIST EN 300 392-11-21 V1.1.1:2003



Page 4Draft prETS 300 392-11-21: September 19964.3Allocation of FEs to physical equipment.214.4Inter-working considerations.21History.22SIST EN 300 392-11-21 V1.1.1:2003



Page 5Draft prETS 300 392-11-21: September 1996ForewordThis draft European Telecommunication Standard (ETS) has been produced by the Radio Equipment andSystems (RES) Technical Committee of the European Telecommunications Standards Institute (ETSI),and is now submitted for the Public Enquiry phase of the ETSI standards approval procedure.This ETS is a multi-part standard and will consist of the following parts:Part 1:"General network design".Part 2:"Air Interface (AI)".Part 3:"Inter-working", (DE/RES-06001-3).Part 4:"Gateways", (DE/RES-06001-4).Part 5:"Terminal equipment interface", (DE/RES-06001-5).Part 6:"Line connected stations", (DE/RES-06001-6).Part 7:"Security".Part 8:"Management services", (DE/RES-06001-8).Part 9:"Performance objectives", (DE/RES-06001-9).Part 10:"Supplementary Services (SS) Stage 1".Part 11:"Supplementary Services (SS) Stage 2".Part 12:"Supplementary Services (SS) Stage 3".Part 13:"SDL Model of the Air Interface".Part 14:"PICS Proforma", (DE/RES-06001-14).Part 15:"Inter-working - Extended Operations", (DE/RES-06001-15).Proposed transposition datesDate of latest announcement of this ETS (doa):3 months after ETSI publicationDate of latest publication of new National Standardor endorsement of this ETS (dop/e):6 months after doaDate of withdrawal of any conflicting National Standard (dow):6 months after doaSIST EN 300 392-11-21 V1.1.1:2003



Page 6Draft prETS 300 392-11-21: September 1996Blank pageSIST EN 300 392-11-21 V1.1.1:2003



Page 7Draft prETS 300 392-11-21: September 19961ScopeThis European Telecommunication Standard (ETS) defines the stage 2 specification of theSupplementary Service Ambience Listening (SS-AL) for the Trans-European Trunked Radio (TETRA) asprovided by European operators. Stage 2 identifies the functional entities involved in the supplementaryservice and the information flows between them.Charging principles and Man-Machine Interface (MMI) are outside the scope of this ETS.The SS-AL enables a served user to place a TETRA Mobile Station (MS) or Line Station (LS) into aspecial type of voice call teleservice whereby the called MS (or LS) transmits without any action from, orindication to, the affected user. The teleservice may include a second listening party.2Normative referencesThis ETS incorporates, by dated or undated reference, provisions from other publications.These†normative references are cited at the appropriate places in the text and the publications are listedhereafter. For dated references, subsequent amendments to, or revisions of, any of these publicationsapply to this ETS only when incorporated in it by amendment or revision. For undated references the latestedition of the publication referred to applies.[1]CCITT Recommendation I.130 (1988): "Method for the characterization oftelecommunication services supported by an ISDN and network capabilities ofan ISDN".[2]ETS 300 392-2: "Radio Equipment and Systems (RES); Trans-EuropeanTrunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air Interface (AI)". [3]ETS 300 392-1: "Radio Equipment and Systems (RES); Trans-EuropeanTrunked Radio (TETRA); Voice plus Data (V+D); Part 1: General NetworkDesign". [4]ITU-T Recommendation Z.100 (1993): "Specification and Description Language(SDL)".3Definitions and abbreviations3.1DefinitionsFor the purposes of this ETS, the following definitions apply:AL call: A call in which ambience listening functionality is requested. During the AL call, the affecteduser's MS (or LS) transmits without any action from, or indication to, the affected user.affected user: The user who is subject to the operation.served user: The user who is invoking this supplementary service.second listening party: A TETRA individual or group which may listen into the AL call.SIST EN 300 392-11-21 V1.1.1:2003



Page 8Draft prETS 300 392-11-21: September 19963.2AbbreviationsFor the purposes of this ETS, the following abbreviations apply:ALAmbience ListeningCCCall ControlCCACall Control (functional entity Agent)FEFunctional EntityGTSIGroup TETRA Subscriber IdentityISDNIntegrated Services Digital NetworkITSIIndividual TETRA Subscriber IdentityLSLine StationMSMobile StationSDL(Functional) Specification and Description LanguageSSSupplementary ServiceNOTE:The abbreviation SS is only used when referring to a specific supplementary service.SwMISwitching and Management InfrastructureTETRATrans-European Trunked Radio4Supplementary Service Ambience Listening (SS-AL) Stage 2 specification4.1Functional model4.1.1Functional model descriptionThe functional model shall comprise the following Functional Entities (FEs):-FE1served user's service agent;-FE2ambience listening control entity in the served user's home system;-FE3affected user's service agent;-FE4generic functional control entity in a visited system with respect to the served user;-FE5second listening party's service agent.The following relationships shall exist between these FEs:-rabetween FE1 and FE2;-rbbetween FE2 and FE3;-rcbetween FE2 and FE4 in different systems;-rdbetween FE4 and FE1;-rebetween FE4 and FE3;-rfbetween FE5 and FE2;-rg between FE5 and FE4.Figure 1 shows these FEs and their relationships.SIST EN 300 392-11-21 V1.1.1:2003



Page 9Draft prETS 300 392-11-21: September 1996SYSTEM 1CCAFE1CCFE2CCAFE3SYSTEM 2CCAFE1CCFE4CCAFE3rarbrcrdreISIServed UserServed UserAffected UserAffected UserCCAFE5Second Listening PartyrfCCAFE5Second Listening PartyrgFigure 1: Operational and management functional model for SS-AL4.1.2Description of FEs4.1.2.1Served user's agent functional entity, FE1The function entity FE1 shall: receive interrogation and invocation information from the served user andinformation (positive or negative acknowledgements) about the executed service request from FE2 inorder to deliver it to the served user.4.1.2.2AL control functional entity, FE2The functional entity FE2 shall:-perform checks, give instructions and perform actions for the data received for interrogation andinvocation;-construct and deliver the PDUs;-provide the affected user's application with applicable SS-AL data by sending it to the affecteduser's service agent FE3 via FE4 if the affected user is located in a different system;-provide the served user's agent functional entity with the positive or negative acknowledgement ofthe requested service. This is sent to FE4 if the served user is in visited system;-given that a second listening party is involved in the AL call, provide the second listening party'sapplication with applicable SS-AL data by sending it to the second listening party's service agentFE5 via FE4 if the second listening party is located in a different system;-if any exception conditions are noticed by SwMI, FE2 stops the execution of the service request andthe AL call will be cleared down;-clear down the AL call if a new incoming call is received for the affected user.SIST EN 300 392-11-21 V1.1.1:2003



Page 10Draft prETS 300 392-11-21: September 19964.1.2.3Affected user's agent functional entity, FE3The functional entity FE3 shall:-receive information of the new AL invocation.;-disable user notification of the call with which AL is invoked.The functional entity FE3 may:-clear down the AL call if the affected user attempts to make a new call, normal call disconnectionprocedures shall apply to the AL call, as specified in ETS 300 392-2 [2];-when the AL call ends FE3 reverts to normal operation;-in one SS-AL invocation there may only be one affected user.4.1.2.4Generic functional control entity, FE4The functional entity FE4 shall:-clear down the AL call if a new incoming call is received for the affected user;-receive information flows from the ambience listening control functional entity, the served user'scontrol functional entity and the affected user's control functional entity.The information flows FE4 shall be able to receive:-acknowledgements sent by an affected user located in its system;-requests and responses sent by ambience listening control entity in SS-AL home system;-requests sent by a served user located in its system.FE4 adds the applicable addressing information to the information flows and they are sent to theirrecipient:-the affected user that is currently in this system for SS-AL invocation;-the SS-AL control entity for the responses sent by the affected user;-the served user that is currently in this system for SS-AL interrogation and invocation;-the second listening party that is currently in this system for SS-AL information.4.1.2.5Second listening party's agent functional entity, FE5The functional entity FE5 shall: receive an information flow for the new AL call set-up.4.2Information flows4.2.1Definition of information flowsIn the tables listing the element type indicates whether the data type is Mandatory (M) or optional (O).4.2.1.1InterrogationSIST EN 300 392-11-21 V1.1.1:2003



Page 11Draft prETS 300 392-11-21: September 19964.2.1.1.1INTERROGATE-REQUESTThis shall be an information flow for the routes ra, rc and rd from FE1 to FE2. The flow shall be sent toFE2 via FE4 if FE1 is in a visited system. The flow is used to interrogate the SS-AL for a specifiedindividual, a list of individuals or a range of individuals. Table 1 lists the elements within theINTERROGATE-REQUEST information flow.Table 1: Content of INTERROGATE-REQUESTElementTypeValueRemarksInterrogated Subscribers Identity(s)MThis may be a single identity,a list or a range of identitiesIf range is given, the first andthe last value is given4.2.1.1.2INTERROGATE-RESULTThis shall be an information flow for the routes ra, rc and rd from FE2 to FE1. The flow shall be sent toFE1 via FE4 if FE1 is in a visited system. The flow shall be used to acknowledge an interrogation requestfor a specified individual, a list of individuals or a range of individuals. Table 2 lists the elements within theINTERROGATE-RESULT information flow.Table 2: Content of INTERROGATE-RESULTElementTypeValueRemarksInterrogated Subscribers Identity(s)MThis may be a single identity,a list or a range of identitiesIf range is given, the first andthe last value is givenResultMinvoked,service not defined for theTETRA id.,rejected for any reason,user not authorized,unknown TETRA identity,parameters not valid orinsufficient informationIndicates if the interrogationwas successful. This valueapplies to all i
...

SLOVENSKI STANDARD
SIST EN 300 392-11-21 V1.1.1:2003
01-december-2003
Prizemni snopovni radio (TETRA) - Govor in podatki (V+D) - 11. del: Dopolnilne
storitve stopnje 2 - 10.-21. del: Poslušanje okolice (AL)
Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary
services stage 2; Sub-part 21: Ambience Listening (AL)
Ta slovenski standard je istoveten z: EN 300 392-11-21 Version 1.1.1
ICS:
33.070.10 Prizemni snopovni radio Terrestrial Trunked Radio
(TETRA) (TETRA)
SIST EN 300 392-11-21 V1.1.1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 300 392-11-21 V1.1.1:2003

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SIST EN 300 392-11-21 V1.1.1:2003

ETSI EN 300 392-11-21 V1.1.1 (2003-04)
European Standard (Telecommunications series)


Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 11: Supplementary services stage 2;
Sub-part 21: Ambience Listening (AL)

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SIST EN 300 392-11-21 V1.1.1:2003
 2 ETSI EN 300 392-11-21 V1.1.1 (2003-04)



Reference
DEN/TETRA-03001-11-21
Keywords
supplementary service, TETRA
ETSI
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SIST EN 300 392-11-21 V1.1.1:2003
 3 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
Contents
Intellectual Property Rights.5
Foreword.5
1 Scope.7
2 References.7
3 Definitions and abbreviations.7
3.1 Definitions.7
3.2 Abbreviations.8
4 Functional model.8
4.1 Functional model description.8
4.2 Description of FEs.9
4.2.1 Served user's agent functional entity, FE1 .9
4.2.2 AL control functional entity in home SwMI, FE2 .9
4.2.3 Affected user's agent functional entity, FE5 .10
4.2.4 AL functional control entity in visited SwMI, FE2 .10
4.2.5 Second listening party's agent functional entity, FE6 .10
5 Information flows.10
5.1 Definition of information flows.10
5.1.1 AL-TX DEMAND.10
5.1.2 AL-TX GRANTED.11
5.1.3 AL-TX INFORM.11
5.1.4 AL-TX INTERRUPT.11
5.1.5 AL-TX REJECT.12
5.1.6 INFORMATION.12
5.1.7 INTERROGATE.12
5.1.8 INTERROGATE ACK.13
5.1.9 INVOKE1.13
5.1.10 INVOKE2.13
5.1.11 INVOKE.13
5.1.12 INVOKE ACK.14
5.1.13 INVOKE1 ACK.14
5.1.14 INVOKE2 ACK.14
5.2 Relationship of information flows to basic call information flows .15
5.3 Service primitives.15
5.4 Information flow sequences .15
5.4.1 General.15
5.4.2 Interrogation.16
5.4.3 Interrogation of AL when FE1 in visited system.16
5.4.4 Invocation with served user and affected user in home system .16
5.4.5 Invocation with served user, affected user and second listening party in home system .17
5.4.6 Invocation with second Listening Party, served user in visited system .18
5.4.7 Invocation with served user in visited system, without second listening party.18
5.4.8 Invocation with affected user in visited system, without second listening party .19
5.4.9 Invocation with affected user in visited system, with second listening party .19
5.4.10 AL call cleardown, with affected user in home system, due to the affected user invoking a new call .20
5.4.11 AL call cleardown, with affected user in visited system, due to a new outgoing call.20
5.4.12 AL call cleardown, with affected user in visited system, due to a new incoming call.21
5.4.13 Affected user engaged in a call.21
5.4.14 Rejection of an ambience listening transmission demand .22
5.5 FE Actions.22
5.5.1 Functional entity actions of FE1 .22
5.5.2 Functional entity actions of FE2 .23
5.5.3 Functional entity actions of visited SwMI FE2.23
5.5.4 Functional entity actions of FE5 .24
ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 4 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
5.5.5 Functional entity actions of FE6 .24
6 Allocation of FEs to physical equipment .24
7 Interworking considerations.25
History .26

ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 5 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
All published ETSI deliverables shall include information which directs the reader to the above source of information.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Project Terrestrial Trunked Radio
(TETRA).
The present document had been submitted to Public Enquiry as ETS 300 392-11-21. During the processing for Vote it
was converted into an EN.
The present document is part 11, sub-part 21 of a multi-part deliverable covering Voice plus Data (V+D), as identified
below:
EN 300 392-1: "General network design";
EN 300 392-2: "Air Interface (AI)";
EN 300 392-3: "Interworking at the Inter-System Interface (ISI)";
ETS 300 392-4: "Gateways basic operation";
EN 300 392-5: "Peripheral Equipment Interface (PEI)";
EN 300 392-7: "Security";
EN 300 392-9: "General requirements for supplementary services";
EN 300 392-10: "Supplementary services stage 1";
EN 300 392-11: "Supplementary services stage 2";
ETS 300 392-11-1: "Call Identification (CI)";
ETS 300 392-11-2: "Call Report (CR)";
ETS 300 392-11-3: "Talking Party Identification (TPI)";
EN 300 392-11-4: "Call Forwarding (CF)";
ETS 300 392-11-5: "List Search Call (LSC)";
ETS 300 392-11-6: "Call Authorized by Dispatcher (CAD)";
ETS 300 392-11-7: "Short Number Addressing (SNA)";
EN 300 392-11-8: "Area Selection (AS)";
ETS 300 392-11-9: "Access Priority (AP)";
EN 300 392-11-10: "Priority Call (PC)";
ETS 300 392-11-11: "Call Waiting (CW)";
EN 300 392-11-12: "Call Hold (CH)";
ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 6 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
ETS 300 392-11-13: "Call Completion to Busy Subscriber (CCBS)";
EN 300 392-11-14: "Late Entry (LE)";
ETS 300 392-11-16: "Pre-emptive Priority Call (PPC)";
EN 300 392-11-17: "Include Call (IC)";
EN 300 392-11-18: "Barring of Outgoing Calls (BOC)";
EN 300 392-11-19: "Barring of Incoming Calls (BIC)";
ETS 300 392-11-20: "Discreet Listening (DL)";
EN 300 392-11-21: "Ambience Listening (AL)";
ETS 300 392-11-22: "Dynamic Group Number Assignment (DGNA)";
ETS 300 392-11-23: "Call Completion on No Reply (CCNR)";
ETS 300 392-11-24: "Call Retention (CRT)";
EN 300 392-12: "Supplementary services stage 3";
ETS 300 392-13: "SDL model of the Air Interface (AI)";
ETS 300 392-14: "Protocol Implementation Conformance Statement (PICS) proforma specification";
TS 100 392-15: "TETRA frequency bands, duplex spacing and channel numbering";
TS 100 392-16: "Network Performance Metrics";
TS 100 392-17: "TETRA V+D and DMO Release 1.1 specifications".

National transposition dates
Date of adoption of this EN: 4 April 2003
Date of latest announcement of this EN (doa): 31 July 2003
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 January 2004
Date of withdrawal of any conflicting National Standard (dow): 31 January 2004

ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 7 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
1 Scope
The present document defines the stage 2 specification of the Supplementary Service Ambience Listening (SS-AL) for
the Terrestrial Trunked Radio (TETRA). Stage 2 identifies the functional entities involved in the supplementary service
and the information flows between them. Aspects relating to all supplementary services are detailed in
EN 300 392-9 [2].
NOTE: The stage 2 description is followed by the stage 3 description, which specifies the encoding rules for the
information flows and process behaviour for the different entities in the SwMI and in the MS.
Charging principles and Man-Machine Interface (MMI) are outside the scope of the present document.
The SS-AL enables a served user to place a TETRA Mobile Station (MS) into a special type of voice call whereby the
called MS transmits without any action from, or indication to, the affected user. The ambience listening call may
include a second listening party.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
[1] ETSI EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 2: Air Interface (AI)".
[2] ETSI EN 300 392-9: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 9: General requirements for supplementary services".
[3] ETSI EN 300 392-12-21: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 12: Supplementary services stage 3; Sub-part 21: Ambience Listening (AL)".
[4] ETSI EN 300 392-10-21: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 10: Supplementary services stage 1; Sub-part 21: Ambience Listening (AL)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
Ambience Listening (AL) call: call in which ambience listening functionality is requested
NOTE: During the AL call, the affected user's MS transmits without any action from, or indication to, the
affected user.
affected user: user whom the served user is listening to
served user: user who invokes this supplementary service and listens to the affected user
ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 8 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
second listening party: TETRA individual or group which additionally listens the AL call
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AL Ambience Listening
FE Functional Entity
ISI InterSystem Interface
ITSI Individual TETRA Subscriber Identity
MS Mobile Station
SS Supplementary Service
NOTE: The abbreviation SS is only used when referring to a specific supplementary service.
SwMI Switching and Management Infrastructure
4 Functional model
4.1 Functional model description
The functional model shall comprise the following Functional Entities (FEs):
- FE1 served user's service agent;
- FE2 ambience listening control entity;
- FE5 affected user's service agent;
- FE6 second listening party's service agent.
The following relationships shall exist between these FEs:
- ra between FE1 and FE2;
- rb between FE2 and FE5;
- rc between FE2s in different SwMIs;
- rd between FE2 and FE1 in a visited SwMI;
- re between FE2 in visited SwMI and FE5 in visited SwMI;
- rf between FE6 and FE2;
- rg between FE6 in visited SwMI and FE2 in a visited SwMI.
Figure 1 shows these FEs and their relationships.
NOTE: Served user FE1 and affected user FE5 can be present only once in each instance and figure 1 gives only
a general view.
ETSI

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SIST EN 300 392-11-21 V1.1.1:2003
 9 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
Second Listening Party

SwMI 1
FE6
CCA
rf
Affected User
Served User
FE1 ra FE2 FE5
rb
CC
CCA CCA
ISI
rc
SwMI 2
Served Uset
Affected User
rd
FE5
FE2
FE1
re
CC CCA
CCA
Second Listening Party
FE6
rg
CCA

Figure 1: Operational and management functional model for SS-AL
4.2 Description of FEs
4.2.1 Served user's agent functional entity, FE1
The function entity FE1 shall:
- receive interrogation and invocation information from the served user and information about the executed
service request from FE2 in order to deliver it to the served user.
4.2.2 AL control functional entity in home SwMI, FE2
The functional entity FE2 shall:
- perform checks and actions for the data received for interrogation and invocation;
- provide the affected user's application with applicable SS-AL data by sending it to the affected user's service
agent FE5 via visited system FE2 if the affected user is located in a different system;
- provide the served user's agent functional entity with the acknowledgement or rejection of the requested
service. This is sent via visited system SwMI FE2 if the served user is in visited system;
- given that a second listening party is involved in the AL call, provide the second listening party's application
with applicable SS-AL data by sending it to the second listening party's service agent FE6 via visited system
SwMI FE2 if the second listening party is located in a different system;
- if any exception conditions are noticed by SwMI, FE2 shall take appropriate action;
- optionally clear down the AL call if a new incoming call is received for the affected user.
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SIST EN 300 392-11-21 V1.1.1:2003
 10 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
4.2.3 Affected user's agent functional entity, FE5
The functional entity FE5 shall:
- receive information of the new AL invocation;
- disable user notification of the call with which AL is invoked.
The functional entity FE5 should clear down the AL call if the affected user attempts to make a new call, normal call
disconnection procedures shall apply to the AL call, as specified in EN 300 392-2 [1].
When the AL call ends FE5 reverts to normal operation.
In one SS-AL invocation there may only be one affected user.
4.2.4 AL functional control entity in visited SwMI, FE2
The functional entity FE2 in visited SwMI shall:
- clear down the AL call if a new incoming call is received for the affected user;
- receive information flows from the ambience listening control functional entity, the served user's control
functional entity and the affected user's control functional entity.
The information flows FE2 in visited SwMI shall be able to receive:
- acknowledgements sent by an affected user located in its system;
- requests and responses sent by ambience listening control entity in SS-AL home system;
- requests sent by a served user located in its system.
FE2 in visited SwMI shall send information flows to their recipient:
- the affected user that is currently in this system for SS-AL invocation;
- the SS-AL control entity for the responses sent by the affected user;
- the served user that is currently in this system for SS-AL interrogation and invocation;
- the second listening party that is currently in this system for SS-AL information.
4.2.5 Second listening party's agent functional entity, FE6
The functional entity FE6 shall: receive an information flow for the new AL call set-up.
5 Information flows
5.1 Definition of information flows
In the tables listing the element type indicates whether the information element is Mandatory (M) or optional (O).
5.1.1 AL-TX DEMAND
AL-TX DEMAND is an optional information flow for the routes ra, rc and rd from FE1 to FE2. The flow is sent to FE2
(group controlling SwMI) via FE2 in visited SwMI if FE1 is in a visited system. The flow is used to invoke
AL-listening for a specified individual user during ongoing group call. Table 1 lists the elements within the
AL-TX DEMAND information flow.
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SIST EN 300 392-11-21 V1.1.1:2003
 11 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
Table 1: Content of AL-TX DEMAND information flow
Element Type
Affected user identity M
TX demand priority M
Encryption control M

NOTE: Addition of other second listening parties, than those already in the ongoing call, is outside the scope of
the present document.
5.1.2 AL-TX GRANTED
AL-TX GRANTED is an optional information flow for routes rb, rc and re from FE2 to FE5. The flow is sent to FE5
via FE2 in visited SwMI, if FE5 is in that visited system. The flow is used to invoke AL-transmission for the specified
individual user during ongoing group call. Table 2 lists the elements within the AL-TX GRANTED information flow.
Table 2: Contents of AL-TX GRANTED information flow
Element Type
Transmission grant M, note
Encryption control M
NOTE: Only value "Transmission granted" is applicable.

5.1.3 AL-TX INFORM
AL-TX INFORM is an optional information flow for the routes rf, rc and rg from FE2 to FE6. The flow is sent via FE2
in visited SwMI, if FE6 is in the visited system. The AL-TX INFORM indicates that the current speech item is an
AL-speech item. Table 3 lists the elements within the AL-TX INFORM information flow.
Table 3: Contents of AL-TX INFORM information flow
Element Type
Affected user identity M
Listening party identity O

5.1.4 AL-TX INTERRUPT
AL-TX INTERRUPT is an optional information flow for the routes ra, rc and rd from FE1 to FE2. The flow is sent via
FE2 in visited SwMI, if FE1 is in the visited system. The flow is used to stop AL-transmission for a specified individual
during ongoing group call. Table 4 lists the elements within the AL-TX INTERRUPT information flow.
Table 4: Content of AL-TX INTERRUPT information flow
Element Type
Affected user identity M

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SIST EN 300 392-11-21 V1.1.1:2003
 12 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
5.1.5 AL-TX REJECT
AL-TX REJECT is an optional information flow for the routes ra, rc and rd from FE2 to FE1. The flow is sent to FE1
via FE2 in visited SwMI if FE1 is in a visited system. The flow is used to give reason why the AL-listening invocation
for a specified individual user during ongoing group call failed. Table 5 lists the elements within the AL-TX REJECT
information flow.
Table 5: Contents of AL-TX REJECT information flow
Element Type Remark
Rejection Cause M rejected for undefined reason;
accepted;
service not supported;
user not authorized;
affected user busy;
unknown TETRA identity.

5.1.6 INFORMATION
INFORMATION is an optional information flow for the routes rc, rf and rg from FE2 to FE6. The flow is sent to FE6
via FE2 in visited SwMI if FE6 is in a visited system. The flow is used to inform a second listening party that the
incoming call is an AL call. Table 6 lists the elements within the INFORMATION information flow.
Table 6: Content of INFORMATION information flow
Element Type
Affected user identity M

5.1.7 INTERROGATE
INTERROGATE is an optional information flow for the routes ra, rc and rd from FE1 to FE2. The flow is sent to FE2
via FE2 in visited SwMI if FE1 is in a visited system. The flow is used to interrogate the SS-AL for a specified
individual, a list of individuals or a range of individuals. Table 7 lists the elements within the INTERROGATE
information flow.
Table 7: Content of INTERROGATE information flow
Element Type Remarks
Interrogated subscribers identity(s) M This may be a single identity, a
list or a range of identities.

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 13 ETSI EN 300 392-11-21 V1.1.1 (2003-04)
5.1.8 INTERROGATE ACK
INTERROGATE ACK is an optional information flow for the routes ra, rc and rd from FE2 to FE1. The flow is sent to
FE1 via FE2 in visited SwMI if FE1 is in a visited system. The flow is used to acknowledge an interrogation request for
a specified individual, a list of individuals or a range of individuals. Table 8 lists the elements within the
INTERROGATE ACK information flow.
If INTERROGATE is supported then support of the INTERROGATE ACK is mandatory.
Table 8: Content of INTERROGATE ACK information flow
Element Type Remarks
Interrogated subscribers identity(s) M This may be a single identity, a list or a range
of identities
Result M rejected for undefined reason;
SS-AL invoked for the TETRA identity,
SS-AL not invoked for the TETRA identity;
user not authorized;
unknown TETRA identity;
parameters not valid; or
insufficient information.

5.1.9 INVOKE1
INVOKE1 s an optional information flow for the routes ra, rc and rd from FE1 to FE2. The flow is sent to FE2 via FE2
in visited SwMI if FE1 is in a visited system. The flow is used to request invocation of SS-AL for a specified
individual. Table 9 lists the elements within the INVOKE1 information flow.
Table 9: Content of INVOKE1 information flow
Element Type
Affected user identity M

5.1.10 INVOKE2
INVOKE2 is an optional information flow for the routes ra, rc and rd from FE1 to FE2. The flow is sent to FE2 via FE2
in visited SwMI if FE1 is in a visited system. The flow is used to include a second listening party into an ongoing AL
call. Table 10 lists the elements within the INVOKE2 information flow.
Table 10: Content of INVOKE2 information flow
Element Type
Second listening party identity M

5.1.11 INVOKE
INVOKE is a mandatory information flow for the routes rb, rc and re from FE2 to FE5. The flow is sent to FE5 via FE2
in visited SwMI if FE5 is in a visited system. The flow is used to invoke ambience listening in a specified individual.
Table 11 lists the elements within the INVOKE information flow. This flow shall stop to the application layer and not to
the affected user.
Table 11: Content of INVOKE information flow
Element Type
Affected user identity M

ETSI

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