SIST EN 300 392-3-8 V1.4.1:2020

ETSI EN 300 392-3-8 V1.4.1 (2020-04)






EUROPEAN STANDARD
Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI);
Sub-part 8: Generic Speech Format Implementation

---------------------- Page: 1 ----------------------
2 ETSI EN 300 392-3-8 V1.4.1 (2020-04)



Reference
REN/TCCE-03256
Keywords
interworking, radio, TETRA, V+D
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2020.
All rights reserved.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 5
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 8
4 Overview . 9
5 ISI Traffic PDU format and procedures . 9
5.1 General on ISI traffic PDU contents. 9
5.2 TETRA ISI payload. 10
5.2.1 TETRA ISI payload encoding . 10
5.2.2 ISI Traffic PDU . 10
5.3 ISI Traffic PDU information elements . 10
5.3.1 ISI PDU framing rate . 10
5.3.2 ISI PDU frame number . 11
5.3.3 Information element control . 11
5.3.4 Additional information . 11
5.3.5 Call reference . 12
5.3.6 Traffic type . 12
5.3.7 Contents control . 12
5.3.8 Contents control and payload. 12
Annex A (informative): TETRA ISI channel mapping . 15
A.1 TETRA ISI channel mapping for E1 B-channels . 15
Annex B (normative): User information transport over E1 . 16
B.1 General . 16
B.2 LAPF Usage . 16
B.3 HDLC usage . 17
Annex C (informative): Physical layer and mapping . 19
C.1 Physical layer . 19
C.2 Mapping structure . 19
Annex D (normative): User information transport in RTP session . 20
D.1 General . 20
D.2 RTP usage . 20
Annex E (informative): Change requests . 21
History . 22

ETSI

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4 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This European Standard (EN) has been produced by ETSI Technical Committee TETRA and Critical Communications
Evolution (TCCE).
The present document is part 3, sub-part 8 of a multi-part deliverable covering the Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D), as identified below:
Part 1: "General network design";
Part 2: "Air Interface (AI)";
Part 3: "Interworking at the Inter-System Interface (ISI)":
Sub-part 1: "General design";
Sub-part 2: "Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 3: "Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 4: "Additional Network Feature Short Data Service (ANF-ISISDS)";
Sub-part 5: "Additional Network Feature for Mobility Management (ANF-ISIMM)";
Sub-part 6: "Speech format implementation for circuit mode transmission";
Sub-part 7: "Speech Format Implementation for Packet Mode Transmission";
Sub-part 8: "Generic Speech Format Implementation";
Sub-part 9: "Transport layer independent, General design";
Sub-part 10: "General design, PSS1 over E.1";
Sub-part 11: "General design, SIP/IP";
Sub-part 12: "Transport layer independent Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 13: "Transport layer independent Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 14: "Transport layer independent Additional Network Feature Short Data Service (ANF-ISISDS)";
ETSI

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5 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
Sub-part 15: Transport layer independent Additional Network Feature, Mobility Management
(ANF-ISIMM)";
Part 4: "Gateways basic operation";
Part 5: "Peripheral Equipment Interface (PEI)";
Part 7: "Security";
Part 9: "General requirements for supplementary services";
Part 10: "Supplementary services stage 1";
Part 11: "Supplementary services stage 2";
Part 12: "Supplementary services stage 3";
Part 13: "SDL model of the Air Interface (AI)";
Part 14: "Protocol Implementation Conformance Statement (PICS) proforma specification";
Part 15: "TETRA frequency bands, duplex spacings and channel numbering";
Part 16: "Network Performance Metrics";
Part 17: "TETRA V+D and DMO specifications";
Part 18: "Air interface optimized applications";
Part 19: "Interworking between TETRA and Broadband systems".
NOTE 1: Part 3, sub-parts 6 and 7 (Speech format implementation), part 4, sub-part 3 (Data networks gateway),
part 10, sub-part 15 (Transfer of control), part 13 (SDL) and part 14 (PICS) of this multi-part deliverable
are in status "historical" and are not maintained.
NOTE 2: Some parts are also published as Technical Specifications such as ETSI TS 100 392-2 and those may be
the latest version of the document.
For all subparts in the TETRA specification ETSI EN 300 392-3, "Interworking at the Inter-System Interface (ISI)" the
terms ISI and TETRA ISI are equivalent.
National transposition dates
Date of adoption of this EN: 13 November 2019
Date of latest announcement of this EN (doa): 31 July 2020
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 January 2021
Date of withdrawal of any conflicting National Standard (dow): 31 January 2021
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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6 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
Introduction
The present document defines the solution in the speech transportation format that applies in the ISI.
The present document also describes the transportation of ISI speech transmission over E1 time-division multiplexed
digital lines using LAPF/HDLC encapsulation (when ISI signalling uses PSS1 as transport layer) and over IP network
using RTP and UDP encapsulation (when ISI signalling adopts SIP as transport layer).
ETSI

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7 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
1 Scope
The present document specifies speech transmission format implementation independent of SwMI type.
The present document defines the format of user information that is transported between two SwMIs using the TETRA
ISI.
The present document covers how TETRA air interface circuit mode traffic is encoded for transport over various media.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air
Interface (AI)".
[2] Void.
[3] ETSI EN 300 395-2: "Terrestrial Trunked Radio (TETRA); Speech codec for full-rate traffic
channel; Part 2: TETRA codec".
[4] ETSI ETS 300 402-3: "Integrated Services Digital Network (ISDN); Digital Subscriber Signalling
System No. one (DSS1) protocol; Data link layer; Part 3: Frame relay protocol specification".
[5] IETF RFC 3550: "RTP: A Transport Protocol for Real Time Applications".
[6] IETF RFC 4566: "SDP: Session Description Protocol".
[7] ETSI EN 300 392-3-10: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI); Sub-part 10: General design, PSS1 over
E.1".
ETSI

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8 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T G.703: "Physical/electrical characteristics of hierarchical digital
interfaces".
[i.2] Recommendation ITU-T G.704: "Synchronous frame structures used at 1544, 6312, 2048, 8448
and 44 736 kbit/s hierarchical levels".
[i.3] Recommendation ITU-T I.431: "Primary rate User-Network interface - Layer 1 specification".
[i.4] Recommendation ITU-T I.233.1: "ISDN Frame Relaying Bearer Service".
[i.5] Recommendation ITU-T Q.922: "Digital subscriber Signalling System No. 1 (DSS 1); Data Link
Layer; ISDN Data Link Layer Specification for Frame Mode Bearer Services".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
ISI PDU frame rate: nominal time between start of two consecutive ISI Traffic PDUs
NOTE: There may be gaps in the flow of the ISI speech frames so that a ISI speech frame is missing in its normal
time position.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACELP Algebraic CELP
AI Air Interface
BECN Backward Explicit Congestion Notification
CR Change Request
CSRC Contributing Source
DE Discard Eligibility indicator
DLCI Data Link Connection Identifier
DMO Direct Mode Operation
E1 European format for digital transmission
ETS European Technical Specification
FCS Frame Check Sequence
ETSI

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9 ETSI EN 300 392-3-8 V1.4.1 (2020-04)
FECN Forward Explicit Congestion Notification
HDLC High level Data Link Control
IETF Internet Engineering Task Force
ISDN Integrated Services Digital Network
IP Internet protocol
ISI Inter System Interface
ITU-T International Telecommunication Union – Telecommunication Standardization Sector
LAPF Link Access Procedures to Frame mode bearer services
MAC Media Access Control
PDU Protocol Data Unit
PEI Peripheral Equipment Interface
PICS Protocol Implementation Conformance Statement
PSS1 Private Network Signalling System Number 1
PVC Permanent Virtual Circuit
RFC Request For Comment
RoHC Robust header Compression
RTCP Real-time Control Protocol
RTP Real-time Transport Protocol
SDL Specification and Description Language
SIP Session Initiation Protocol
SSRC Synchronization Source
SwMI Switching and Management Infrastructure
TDMA Time Division Multiple Access
TETRA Terrestrial Trunked Radio
UDP User Datagram Protocol
V+D Voice plus Data
4 Overview
Independently of SwMI implementation, TETRA speech and circuit mode data traffic and U-plane payload is carried in
packets between two TETRA systems. The TETRA traffic and U-plane payload is carried in ISI traffic PDUs that may
be transported in various media.
Since the transmission defined in the present document is "packet mode", packets may be subject to jitter. The
maximum jitter is a SwMI specific characteristic. The value of the allowable maximum jitter value is outside the scope
of the present document.
5 ISI Traffic PDU format and procedures
5.1 General on ISI traffic PDU contents
As TETRA is a radio system normally at least one end of the communication is using air interface. The structure of the
TETRA air interface sets some requirements on the ISI traffic PDU contents and format on the ISI. The main structure
of the air interface and speech encoding is retained and ISI traffic PDU supports:
• 170/3 ms (~56,67 ms) and 60 ms ISI traffic PDU rate;
• ACELP speech coding and reservation for other codecs; and
• Call reference.
The call reference is used to link the traffic and call instance together especially in scenarios where no virtual
connection is applied.
Optionally a fully stolen or otherwise not available speech
...

Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)






EUROPEAN STANDARD
Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI);
Sub-part 8: Generic Speech Format Implementation

---------------------- Page: 1 ----------------------
2 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)



Reference
REN/TCCE-03256
Keywords
interworking, radio, TETRA, V+D
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2019.
All rights reserved.

TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
TM TM
3GPP and LTE are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI

---------------------- Page: 2 ----------------------
3 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 5
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 8
4 Overview . 9
5 ISI Traffic PDU format and procedures . 9
5.1 General on ISI traffic PDU contents. 9
5.2 TETRA ISI payload. 10
5.2.1 TETRA ISI payload encoding . 10
5.2.2 ISI Traffic PDU . 10
5.3 ISI Traffic PDU information elements . 10
5.3.1 ISI PDU framing rate . 10
5.3.2 ISI PDU frame number . 11
5.3.3 Information element control . 11
5.3.4 Additional information . 11
5.3.5 Call reference . 12
5.3.6 Traffic type . 12
5.3.7 Contents control . 12
5.3.8 Contents control and payload. 12
Annex A (informative): TETRA ISI channel mapping . 15
A.1 TETRA ISI channel mapping for E1 B-channels . 15
Annex B (normative): User information transport over E1 . 16
B.1 General . 16
B.2 LAPF Usage . 16
B.3 HDLC usage . 17
Annex C (informative): Physical layer and mapping . 19
C.1 Physical layer . 19
C.2 Mapping structure . 19
Annex D (normative): User information transport in RTP session . 20
D.1 General . 20
D.2 RTP usage . 20
Annex E (informative): Change requests . 21
History . 22

ETSI

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4 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This draft European Standard (EN) has been produced by ETSI Technical Committee TETRA and Critical
Communications Evolution (TCCE), and is now submitted for the combined Public Enquiry and Vote phase of the
ETSI standards EN Approval Procedure.
The present document is part 3, sub-part 8 of a multi-part deliverable covering the Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D), as identified below:
Part 1: "General network design";
Part 2: "Air Interface (AI)";
Part 3: "Interworking at the Inter-System Interface (ISI)":
Sub-part 1: "General design";
Sub-part 2: "Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 3: "Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 4: "Additional Network Feature Short Data Service (ANF-ISISDS)";
Sub-part 5: "Additional Network Feature for Mobility Management (ANF-ISIMM)";
Sub-part 6: "Speech format implementation for circuit mode transmission";
Sub-part 7: "Speech Format Implementation for Packet Mode Transmission";
Sub-part 8: "Generic Speech Format Implementation";
Sub-part 9: "Transport layer independent, General design";
Sub-part 10: "General design, PSS1 over E.1";
Sub-part 11: "General design, SIP/IP";
Sub-part 12: "Transport layer independent Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 13: "Transport layer independent Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 14: "Transport layer independent Additional Network Feature Short Data Service (ANF-ISISDS)";
ETSI

---------------------- Page: 4 ----------------------
5 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
Sub-part 15: Transport layer independent Additional Network Feature, Mobility Management
(ANF-ISIMM)";
Part 4: "Gateways basic operation";
Part 5: "Peripheral Equipment Interface (PEI)";
Part 7: "Security";
Part 9: "General requirements for supplementary services";
Part 10: "Supplementary services stage 1";
Part 11: "Supplementary services stage 2";
Part 12: "Supplementary services stage 3";
Part 13: "SDL model of the Air Interface (AI)";
Part 14: "Protocol Implementation Conformance Statement (PICS) proforma specification";
Part 15: "TETRA frequency bands, duplex spacings and channel numbering";
Part 16: "Network Performance Metrics";
Part 17: "TETRA V+D and DMO specifications";
Part 18: "Air interface optimized applications";
Part 19: "Interworking between TETRA and Broadband systems".
NOTE 1: Part 3, sub-parts 6 and 7 (Speech format implementation), part 4, sub-part 3 (Data networks gateway),
part 10, sub-part 15 (Transfer of control), part 13 (SDL) and part 14 (PICS) of this multi-part deliverable
are in status "historical" and are not maintained.
NOTE 2: Some parts are also published as Technical Specifications such as ETSI TS 100 392-2 and those may be
the latest version of the document.
For all subparts in the TETRA specification ETSI EN 300 392-3, "Interworking at the Inter-System Interface (ISI)" the
terms ISI and TETRA ISI are equivalent.

Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 6 months after doa

Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

---------------------- Page: 5 ----------------------
6 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
Introduction
The present document defines the solution in the speech transportation format that applies in the ISI.
The present document also describes the transportation of ISI speech transmission over E1 time-division multiplexed
digital lines using LAPF/HDLC encapsulation (when ISI signalling uses PSS1 as transport layer) and over IP network
using RTP and UDP encapsulation (when ISI signalling adopts SIP as transport layer).
ETSI

---------------------- Page: 6 ----------------------
7 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
1 Scope
The present document specifies speech transmission format implementation independent of SwMI type.
The present document defines the format of user information that is transported between two SwMIs using the TETRA
ISI.
The present document covers how TETRA air interface circuit mode traffic is encoded for transport over various media.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air
Interface (AI)".
[2] Void.
[3] ETSI EN 300 395-2: "Terrestrial Trunked Radio (TETRA); Speech codec for full-rate traffic
channel; Part 2: TETRA codec".
[4] ETSI ETS 300 402-3: "Integrated Services Digital Network (ISDN); Digital Subscriber Signalling
System No. one (DSS1) protocol; Data link layer; Part 3: Frame relay protocol specification".
[5] IETF RFC 3550: "RTP: A Transport Protocol for Real Time Applications".
[6] IETF RFC 4566: "SDP: Session Description Protocol".
[7] ETSI EN 300 392-3-10: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI); Sub-part 10: General design, PSS1 over
E.1".
ETSI

---------------------- Page: 7 ----------------------
8 Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T G.703: "Physical/electrical characteristics of hierarchical digital
interfaces".
[i.2] Recommendation ITU-T G.704: "Synchronous frame structures used at 1544, 6312, 2048, 8448
and 44 736 kbit/s hierarchical levels".
[i.3] Recommendation ITU-T I.431: "Primary rate User-Network interface - Layer 1 specification".
[i.4] Recommendation ITU-T I.233.1: "ISDN Frame Relaying Bearer Service".
[i.5] Recommendation ITU-T Q.922: "Digital subscriber Signalling System No. 1 (DSS 1); Data Link
Layer; ISDN Data Link Layer Specification for Frame Mode Bearer Services".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
ISI PDU frame rate: nominal time between start of two consecutive ISI Traffic PDUs
NOTE: There may be gaps in the flow of the ISI speech frames so that a ISI speech frame is missing in its normal
time position.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACELP Algebraic CELP
AI Air Interface
BECN Backward Explicit Congestion Notification
CR Change Request
CSRC Contributing Source
DE Discard Eligibility indicator
DLCI Data Link Connection Identifier
DMO Direct Mode Operation
E1 European format for digital transmission
ETS European Technical Specification
FCS Frame Check Sequence
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FECN Forward Explicit Congestion Notification
HDLC High level Data Link Control
IETF Internet Engineering Task Force
ISDN Integrated Services Digital Network
IP Internet protocol
ISI Inter System Interface
ITU-T International Telecommunication Union – Telecommunication Standardization Sector
LAPF Link Access Procedures to Frame mode bearer services
MAC Media Access Control
MS Mobile Station
PDU Protocol Data Unit
PEI Peripheral Equipment Interface
PICS Protocol Implementation Conformance Statement
PSS1 Private Network Signalling System Number 1
PVC Permanent Virtual Circuit
RFC Request For Comment
RoHC Robust header Compression
RTCP Real-time Control Protocol
RTP Real-time Transport Protocol
SDL Specification and Description Language
SIP Session Initiation Protocol
SSRC Synchronization Source
SwMI Switching and Management Infrastructure
TDMA Time Division Multiple Access
TETRA Terrestrial Trunked Radio
UDP User Datagram Protocol
V+D Voice plus Data
4 Overview
Independently of SwMI implementation, TETRA speech and circuit mode data traffic and U-plane payload is carried in
packets between two TETRA systems. The TETRA traffic and U-plane payload is carried in ISI traffic PDUs that may
be transported in various media.
Since the transmission defined in the present document is "packet mode", packets may be subject to jitter. The
maximum jitter is a SwMI specific characteristic. The value of the allowable maximum jitter value is outside the scope
of the present document.
5 ISI Traffic PDU format and procedures
5.1 General on ISI traffic PDU contents
As TETRA is a radio system normally at least one end of the communication is using air interface. The structure of the
TETRA air interface sets some requirements on the ISI traffic PDU contents and format on the ISI. The main structure
of the air interface and speech encoding is retained and ISI traffic PDU supports:
• 170/3 ms (~56,67 ms) and 60 ms ISI traffic PDU rate;
• ACELP speech coding and reservation for other codecs; and
• Call reference.
The call reference is used to link the traffic and call instance together especially in scenarios
...

SLOVENSKI STANDARD
oSIST prEN 300 392-3-8 V1.4.0:2019
01-november-2019
Prizemni snopovni radio (TETRA) - Govor in podatki (V+D) - 3. del: Medsebojno
delovanje na medsistemskem vmesniku (ISI) - 8. poddel: Izvajanje splošnega
formata govora
Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 3: Interworking at the
Inter-System Interface (ISI) - Sub-part 8: Generic Speech Format Implementation
Ta slovenski standard je istoveten z: ETSI EN 300 392-3-8 V1.4.0 (2019-08)
ICS:
33.070.10 Prizemni snopovni radio Terrestrial Trunked Radio
(TETRA) (TETRA)
oSIST prEN 300 392-3-8 V1.4.0:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 300 392-3-8 V1.4.0:2019
Draft ETSI EN 300 392-3-8 V1.4.0 (2019-08)






EUROPEAN STANDARD
Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI);
Sub-part 8: Generic Speech Format Implementation

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Reference
REN/TCCE-03256
Keywords
interworking, radio, TETRA, V+D
ETSI
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ETSI

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Contents
Intellectual Property Rights . 4
Foreword . 4
Modal verbs terminology . 5
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definition of terms, symbols and abbreviations . 8
3.1 Terms . 8
3.2 Symbols . 8
3.3 Abbreviations . 8
4 Overview . 9
5 ISI Traffic PDU format and procedures . 9
5.1 General on ISI traffic PDU contents. 9
5.2 TETRA ISI payload. 10
5.2.1 TETRA ISI payload encoding . 10
5.2.2 ISI Traffic PDU . 10
5.3 ISI Traffic PDU information elements . 10
5.3.1 ISI PDU framing rate . 10
5.3.2 ISI PDU frame number . 11
5.3.3 Information element control . 11
5.3.4 Additional information . 11
5.3.5 Call reference . 12
5.3.6 Traffic type . 12
5.3.7 Contents control . 12
5.3.8 Contents control and payload. 12
Annex A (informative): TETRA ISI channel mapping . 15
A.1 TETRA ISI channel mapping for E1 B-channels . 15
Annex B (normative): User information transport over E1 . 16
B.1 General . 16
B.2 LAPF Usage . 16
B.3 HDLC usage . 17
Annex C (informative): Physical layer and mapping . 19
C.1 Physical layer . 19
C.2 Mapping structure . 19
Annex D (normative): User information transport in RTP session . 20
D.1 General . 20
D.2 RTP usage . 20
Annex E (informative): Change requests . 21
History . 22

ETSI

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Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This draft European Standard (EN) has been produced by ETSI Technical Committee TETRA and Critical
Communications Evolution (TCCE), and is now submitted for the combined Public Enquiry and Vote phase of the
ETSI standards EN Approval Procedure.
The present document is part 3, sub-part 8 of a multi-part deliverable covering the Terrestrial Trunked Radio (TETRA);
Voice plus Data (V+D), as identified below:
Part 1: "General network design";
Part 2: "Air Interface (AI)";
Part 3: "Interworking at the Inter-System Interface (ISI)":
Sub-part 1: "General design";
Sub-part 2: "Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 3: "Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 4: "Additional Network Feature Short Data Service (ANF-ISISDS)";
Sub-part 5: "Additional Network Feature for Mobility Management (ANF-ISIMM)";
Sub-part 6: "Speech format implementation for circuit mode transmission";
Sub-part 7: "Speech Format Implementation for Packet Mode Transmission";
Sub-part 8: "Generic Speech Format Implementation";
Sub-part 9: "Transport layer independent, General design";
Sub-part 10: "General design, PSS1 over E.1";
Sub-part 11: "General design, SIP/IP";
Sub-part 12: "Transport layer independent Additional Network Feature Individual Call (ANF-ISIIC)";
Sub-part 13: "Transport layer independent Additional Network Feature Group Call (ANF-ISIGC)";
Sub-part 14: "Transport layer independent Additional Network Feature Short Data Service (ANF-ISISDS)";
ETSI

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Sub-part 15: Transport layer independent Additional Network Feature, Mobility Management
(ANF-ISIMM)";
Part 4: "Gateways basic operation";
Part 5: "Peripheral Equipment Interface (PEI)";
Part 7: "Security";
Part 9: "General requirements for supplementary services";
Part 10: "Supplementary services stage 1";
Part 11: "Supplementary services stage 2";
Part 12: "Supplementary services stage 3";
Part 13: "SDL model of the Air Interface (AI)";
Part 14: "Protocol Implementation Conformance Statement (PICS) proforma specification";
Part 15: "TETRA frequency bands, duplex spacings and channel numbering";
Part 16: "Network Performance Metrics";
Part 17: "TETRA V+D and DMO specifications";
Part 18: "Air interface optimized applications";
Part 19: "Interworking between TETRA and Broadband systems".
NOTE 1: Part 3, sub-parts 6 and 7 (Speech format implementation), part 4, sub-part 3 (Data networks gateway),
part 10, sub-part 15 (Transfer of control), part 13 (SDL) and part 14 (PICS) of this multi-part deliverable
are in status "historical" and are not maintained.
NOTE 2: Some parts are also published as Technical Specifications such as ETSI TS 100 392-2 and those may be
the latest version of the document.
For all subparts in the TETRA specification ETSI EN 300 392-3, "Interworking at the Inter-System Interface (ISI)" the
terms ISI and TETRA ISI are equivalent.

Proposed national transposition dates
Date of latest announcement of this EN (doa): 3 months after ETSI publication
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 6 months after doa
Date of withdrawal of any conflicting National Standard (dow): 6 months after doa

Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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Introduction
The present document defines the solution in the speech transportation format that applies in the ISI.
The present document also describes the transportation of ISI speech transmission over E1 time-division multiplexed
digital lines using LAPF/HDLC encapsulation (when ISI signalling uses PSS1 as transport layer) and over IP network
using RTP and UDP encapsulation (when ISI signalling adopts SIP as transport layer).
ETSI

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1 Scope
The present document specifies speech transmission format implementation independent of SwMI type.
The present document defines the format of user information that is transported between two SwMIs using the TETRA
ISI.
The present document covers how TETRA air interface circuit mode traffic is encoded for transport over various media.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference/.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air
Interface (AI)".
[2] Void.
[3] ETSI EN 300 395-2: "Terrestrial Trunked Radio (TETRA); Speech codec for full-rate traffic
channel; Part 2: TETRA codec".
[4] ETSI ETS 300 402-3: "Integrated Services Digital Network (ISDN); Digital Subscriber Signalling
System No. one (DSS1) protocol; Data link layer; Part 3: Frame relay protocol specification".
[5] IETF RFC 3550: "RTP: A Transport Protocol for Real Time Applications".
[6] IETF RFC 4566: "SDP: Session Description Protocol".
[7] ETSI EN 300 392-3-10: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI); Sub-part 10: General design, PSS1 over
E.1".
ETSI

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2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE 1: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
NOTE 2: Note that for the TETRA standards, the reference is always to a European Standard (ETSI EN 300 xxx) if
such has been published, but the latest version of that standard can be either an EN or a Technical
Specification (ETSI TS 100 xxx), even if this is not visible in the reference list.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T G.703: "Physical/electrical characteristics of hierarchical digital
interfaces".
[i.2] Recommendation ITU-T G.704: "Synchronous frame structures used at 1544, 6312, 2048, 8448
and 44 736 kbit/s hierarchical levels".
[i.3] Recommendation ITU-T I.431: "Primary rate User-Network interface - Layer 1 specification".
[i.4] Recommendation ITU-T I.233.1: "ISDN Frame Relaying Bearer Service".
[i.5] Recommendation ITU-T Q.922: "Digital subscriber Signalling System No. 1 (DSS 1); Data Link
Layer; ISDN Data Link Layer Specification for Frame Mode Bearer Services".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
ISI PDU frame rate: nominal time between start of two consecutive ISI Traffic PDUs
NOTE: There may be gaps in the flow of the ISI speech frames so that a ISI speech frame is missing in its normal
time position.
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACELP Algebraic CELP
AI Air Interface
BECN Backward Explicit Congestion Notification
CR Change Request
CSRC Contributing Source
DE Discard Eligibility indicator
DLCI Data Link Connection Identifier
DMO Direct Mode Operation
E1 European format for digital transmission
ETS European Technical Specification
FCS Frame Check Sequence
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FECN Forward Explicit Congestion Notification
HDLC High level Data Link Control
IETF Internet Engineering Task Force
ISDN Integrated Services Digital Network
IP Internet protocol
ISI Inter System Interface
ITU-T International Telecommunication Union – Telecommunication Standardization Sector
LAPF Link Access Procedures to Frame mode bearer services
MAC Media Access Control
MS Mobile Station
PDU Protocol Data Unit
PEI Peripheral Equipment Interface
PICS Protocol Implementation Conformance Statement
PSS1 Private Network Signalling System Number 1
PVC Permanent Virtual Circuit
RFC Request For Comment
RoHC Robust header Compression
RTCP Real-time Control Protocol
RTP Real-time Transport Protocol
SDL Specification and Description Language
SIP Session Initiation Protocol
SSRC Synchronization Source
SwMI Switching and Management Infrastructure
TDMA Time Division Multiple Access
TETRA Terrestrial Trunked Radio
UDP User Datagram Protocol
V+D Voice plus Data
4 Overview
Independently of SwMI implementation, TETRA speech and circuit mode data traffic and U-plane payload is carried in
packets between two TETRA systems. The TETRA traffic and U-plane payload is carried in ISI traffic PDUs that may
be transported in various media.
Since the transmission defined in the present document is "packet mode", packets may be subject to jitter. The
maximum jitter is a SwMI specific characteristic. The value of the allowable maximum jitter value is outside the scope
of the present document.
5 ISI Traffic PDU format and procedures
5.1 General on ISI traffic PDU contents
As TETRA is a radio system normally at least one end of the communication is using air interface. The structure of the
TETRA air interface sets some requirements on the ISI traffic PDU contents and format on the ISI. The main structure
of the air interface and speech encoding is retained and ISI traffic PDU supports:
• 170/3 ms (~56,67 ms) and 60 ms ISI traffic PDU rate;
• ACELP speech coding and reservation for other codecs; and
• Call reference.
The call reference is used to link the traffic and call instance together especially in scenarios where no virtual
connection is applied.
Optionally a fully stolen or otherwise not available speech frame may be indicated to help an easier re-use of that
timeslot for other signalling purposes at the terminating system.
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5.2 TETRA ISI payload
5.2.1 TETRA ISI payload encoding
The protocol has been designed to support TETRA speech codec frames (half slot/ full slot), circuit mode data and
U-plane services. However, the present document only describes in detail the ISI traffic PDU formats for TETRA
speech codec frames (single and dual) and U-plane services. Generic payload structure is presented in figure 5.1.
Payload Header Payload Block 1 Payload Block 2

Figure 5.1: TETRA payload structure
The Payload header (Contents control information element) tells the contents of the Payload blocks 1 and 2, are they
carrying TETRA speech, U-Plane payload or no traffic.
5.2.2 ISI Traffic PDU
The traffic PDU is comprised of the following information elements, see table 5.1:
• call reference: this information element links the traffic PDU and call instance together;
• traffic type: this information element shall identify the type of circuit mode speech/data service;
• ISI PDU framing rate: this information element shall identify whether the speech is continuous flow or
th
TDMA frame of the air interface [1];
contains jumps due to the 18
• ISI PDU frame number: this information element shall indicate the sequence of packets (and may indicate
where the gap due to the ISI PDU framing rate 170/3 ms occurs); and
• contents control and payload: this information element shall define contents of the payload and the payload
blocks.
Table 5.1: ISI Traffic PDU
Information element Length Type C/O/M Remarks
ISI PDU framing rate 1 1 M
ISI PDU frame number 5 1 M
Information element control 2 1 M Shall be set to a value with "Additional information
information element is not present"
Additional information 8 C See notes 1 and 2
Call reference 24 C See note 2
Traffic type 4 1 M
Contents control and payload Variable 1 M
NOTE 1: The Additional information information element allows future expansion of the PDU.
NOTE 2: This information element shall be present as defined in the Information element control information
element.

5.3 ISI Traffic PDU information elements
5.3.1 ISI PDU framing rate
The ISI PDU framing rate information element shall be encoded as defined in table 5.2.
The ISI PDU framing rate allows the destination SwMI to determine the characteristics of the speech packet stream.
Different buffering schemes may then be applied to optimize audio delay for ISI calls.
th
NOTE: Any other jitter in addition to the possible gap due to the 18 TDMA frame on the air interface is outside
the scope of the present document.
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Table 5.2: Contents of the ISI PDU framing rate information element
Information element Length Value Remarks
th
ISI PDU framing rate 1 0
170/3 ms i.e. there is a gap at the 18 TDMA frame position
th
1
60 ms i.e. regular frame rate without a gap for the 18 TDMA
frame

5.3.2 ISI PDU frame number
The ISI PDU frame number information element shall be encoded as defined in table 5.3.
ISI traffic PDUs are numbered from 1 to 17 for transmission purposes for 170/3 ms and 60 ms rate.
The ISI PDU frame number information element can be used by the destination SwMI to monitor the sequence of
speech packets and, with the ISI PDU framing rate 170/3 ms, identify when the frame 18 gap will occur in the packet
stream.
NOTE 1: The ISI PDU frame numbering can be used to optimize buffering on 170/3 ms frame rate.
When the payload message uses ISI PDU framing rate 60 ms, the ISI PDU frame number in the ISI traffic PDU shall be
used as a sequence counter only.
NOTE 2: For the ISI PDU framing rate 60 ms each speech item may start with a value Frame 1.
Table 5.3: Contents of the ISI PDU frame number information element
Information element Length Value Remarks
ISI PDU frame number 5 0 Reserved
1 Frame 1
2 Frame 2
etc. etc.
17 Frame 17
18 Reserved
19 Proprietary
20 Reserved
etc. etc.
31 Reserved

5.3.3 Information element control
The Information element control information element shall be encoded as defined in table 5.4.
Table 5.4: Contents of the information element control information element
Information element Length Value Remarks
Information element 2 0 Additional information information element is not present and
control Call reference information element is not present, see note
1 Additional information information element is not present and
Call reference information element is present, see note
2 Additional information information element is present and Call
reference information element is not present, see note
3 Additional information information element is present and Call
reference information element is present, see note
NOTE: For the present document only the values "0" and "1" are applicable.

5.3.4 Additional information
The Additional information information element shall be encoded as defined in table 5.5.
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Table 5.5: Contents of the Additional information information element
Information element Length Value Remarks
Additional information 8 0 Reserved for additional information
etc. etc.
255 Reserved for additional information

5.3.5 Call reference
The optional Call reference information element shall identify the call (CC instance) to which the traffic PDU belongs
to. Refer to ETSI EN 300 392-3-10 [7].
NOTE: Depending on the scenario the Call reference information may be redundant, if an individual explicit or
implicit (virtual) circuit is used to carry traffic PDUs.
5.3.6 Traffic type
The Traffic type information element shall be encoded as defined in table 5.6.
NOTE: Circuit mode data is outside the scope of the present document.
Table 5.6: Contents of the Traffic type information element
Information element Length Value Remarks
Traffic type 4 0 ACELP, refer to ETSI EN 300 395-2 [3]
1 Reserved for codec 2
2 Reserved for codec 3
3 Proprietary codec
Other Reserved

5.3.7 Contents control
The contents control information element shall be encoded as defined in table 5.7.
NOTE: Traffic 1 and U-plane 1 identify contents of sub-slot 1, and traffic 2 and U-plane 2 identify contents of
sub-slot 2 in the air interface timeslot.
Table 5.7: Contents of the Contents control information element
Information element Length Value Remarks
Contents control 4 0 Traffic 1 + Traffic 2
1 U-plane 1 + Traffic 2
2 U-plane 1 + U-plane 2
3 Reserved
4 Traffic 2 single 30 ms, second half
...