SIST ETS 300 100 E1:2003

• Abstract:

  T/N 23-03

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI ETS 300 100 ed.1 (1992-01) - Integrated Services Digital Network (ISDN); Routing in support of ISUP Version 1 services

SIST ETS 300 100 E1:2003 is a Slovenian standard, identical to ETS 300 100 Edition 1, for routing in Integrated Services Digital Network (ISDN) networks that support ISDN User Part (ISUP) Version 1 services. It gives routing guidance for international gateways, international transit exchanges, and network planning so that ISDN, PSTN and related services can be interconnected in practice.

What does SIST ETS 300 100 E1:2003 specify?

SIST ETS 300 100 E1:2003 specifies how to route calls during ISDN implementation in Europe, with added clarifications and extensions to CCITT Recommendation E.172. It focuses on international routing and interworking rules that matter when ISDN uses ISUP Version 1 or CEPT No. 7 TUP+ in the international network.

The scope is practical rather than general: it applies to routing functions at ISDN international gateways and international transit exchanges, and to network planning for international interconnection. It also names several bearer services and teleservices that are outside its scope.

Annex	What it covers
Annex A, normative	Support of supplementary services in ISDN by ISUP Version 1
Annex B, informative	Bibliography

The document is organized into clauses on scope, normative references, symbols and abbreviations, clarifications to E.172, routing parameters, interworking with PSTN/IDN services, and selection of path/traffic distribution. For a reader, that means the standard moves from basic routing rules to the detailed cases that operators must handle when signalling systems and service capabilities differ.

What are the key requirements of SIST ETS 300 100 E1:2003?

SIST ETS 300 100 E1:2003 is mainly about how to turn a requested service into routing decisions that stay consistent across international and interworking boundaries. The key points are the use of the Transmission Medium Requirement (TMR), the ISUP Preference Indicator (IPI), and the interworking rules between ISUP, TUP, TUP+ and channel associated signalling.

TMR is the routing basis in the international network

Clause 5.1 states that TMR shall be used for routing in the international network and shall be conveyed unchanged across that network. One TMR value shall be used for a specific service request across internetwork boundaries, and routing exchanges shall examine TMR when they make routing decisions.

In practice, this means the service request has to be translated into the right TMR as early as possible, usually in the originating local exchange or at the outgoing international gateway. If the network keeps the same TMR values nationally and internationally, routing stays simpler and less error-prone.

The standard matches services to TMR values

Clause 5.3 links requested services to the relevant TMR value. The document groups services into the three TMR categories used in routing: speech, 3,1 kHz audio, and 64 kbit/s unrestricted.

This matters because the chosen TMR affects which routes are acceptable. For example, some data or digital connectivity requests need 64 kbit/s unrestricted, while ordinary telephony routes may use speech or 3,1 kHz audio.

Signalling systems are assessed by whether they can carry TMR information

Clause 5.2 compares signalling systems such as CCITT ISUP, CEPT TUP+, CCITT TUP, CCITT Signalling system No. 6, CCITT R2 and CCITT Signalling system No. 5 against the TMR values they can support. The table distinguishes between explicit and implicit transfer of TMR information.

For operators, this is a selection aid: if the signalling system cannot carry the needed TMR, the network must rely on other means, such as configuration, special trunks, or network design, or use a different signalling system.

IPI controls whether ISUP is required, preferred or not required

Clause 5.4 assigns IPI values to ISDN services. Closed User Group (CUG) without outgoing access requires ISUP Required, calls initiated by ISDN subscribers use ISUP Preferred as a minimum, and calls originating in the PSTN use ISUP Not Required.

This is the mechanism that tells routing whether an ISDN signalling path is mandatory or whether a fallback path is acceptable. When more than one service is requested, the more restrictive IPI value applies.

Interworking from non-ISUP signalling into ISUP has default fallbacks

Clause 6.1 sets the rules when an incoming TUP or channel associated signalling system does not provide explicit signalling capability or TMR information. In that case, the implicit IPI is ISUP Not Required, and the TMR is set to 3,1 kHz audio unless digital connectivity information is available, in which case 64 kbit/s unrestricted is used.

For practice, that means the network should not assume ISDN signalling is available unless the incoming signalling or external information says so. The routing choice must reflect the best supported bearer capability.

Interworking from ISUP to TUP or channel associated signalling can force fallback or call release

Clause 6.1.2 says that if IPI is ISUP Required, an ISDN route shall be selected if available; if not, the call fails. If TUP is selected and the ISUP TMR indicates 64 kbit/s unrestricted, the TUP indication must support digital connectivity. If channel associated signalling is selected but the network cannot guarantee digital connectivity, the call is released.

This protects service expectations: a digital request must not silently degrade to a route that cannot support it.

TUP+ uses equivalent routing fields and supports mapped fallback

Clause 6.2 states that TUP+ uses Signalling Capability (SC) Requested in the same role as IPI, and ITC Requested in the same role as TMR. Clauses 6.2.1 and 6.2.2 define the mappings between TUP+ and ISUP in both directions.

That gives operators a controlled interworking path between the two signalling worlds. It also shows which supplementary services can still be used when a call falls back to TUP+.

Supplementary services may be preserved, limited or lost on fallback routes

Clause 6.3 and Annex A identify how supplementary services behave when calls stay end-to-end in ISUP or fall back to TUP or TUP+. The tables distinguish services such as CLIP, CLIR, COLP, COLR, CUG, DDI, MSN, SUB, TP and UUS 1 implicit.

In practice, the routing decision is not only about connection setup. It also affects whether a supplementary service survives the route selection, is discarded, or is not supported.

Traffic distribution and path selection should reduce call loss

Clause 7 gives guidance for carriers that offer different facilities to the same destination. It recommends separating ISDN and PSTN traffic where needed, and keeping destination-dependent routing logically separate from the distribution function.

For network planning, the point is to avoid routing all traffic through a carrier that cannot support the required signalling or agreed supplementary services. That reduces avoidable call failures.

What terms does SIST ETS 300 100 E1:2003 define?

• Bearer Capability (BC) - The bearer service information used in routing decisions, especially when deciding what kind of connection can be provided.
• Transmission Medium Requirement (TMR) - The required transmission type for a call, such as speech, 3,1 kHz audio, or 64 kbit/s unrestricted.
• ISUP Preference Indicator (IPI) - The indicator that says whether ISUP is required, preferred, or not required for a call.
• Signalling Capability (SC) - The TUP+ field that plays the same routing role as IPI in ISUP interworking.
• Information Transfer Capability (ITC) - The TUP+ field that plays the same routing role as TMR in ISUP interworking.
• ISUP - ISDN User Part, the signalling part used for ISDN call control in the document.
• TUP+ - Enhanced Telephone User Part, used here with its own routing and interworking rules.
• CUG - Closed User Group, a supplementary service whose routing treatment is explicitly addressed.

Who uses SIST ETS 300 100 E1:2003?

SIST ETS 300 100 E1:2003 is used by telecom network operators, signalling engineers, switch planners, and network architects working on ISDN and PSTN interworking. It is also relevant to administrations and carriers that manage international gateways, international transit exchanges, and destination-dependent routing.

In practice, these users apply the standard when they plan routes, set routing parameters, decide signalling fallbacks, and check whether supplementary services remain supported across mixed networks.

Which standards are used with SIST ETS 300 100 E1:2003?

The standard is built on these referenced documents:

• CCITT Recommendation E.172 - the base routing recommendation that this standard clarifies and extends for European ISDN implementation.
• CCITT Recommendation I.335 - describes the use of the ISUP Transmission Medium Requirement for routing.
• ETS 300 121 - provides the application of ISUP for international ISDN interconnections.
• CCITT Recommendation I.530 - covers interworking between ISDN and PSTN.

The foreword also places the standard in the context of ETR 010, the ETSI Basic Guide on the European ISDN, and notes support for services and capabilities specified in ETS 300 121.

What does the SIST ETS 300 100 E1:2003 document contain?

The document contains routing guidance, parameter mapping tables, and interworking rules for ISDN in the international network. It includes a table comparing signalling systems against TMR values, a table mapping requested services to TMR values, and several tables that map ISUP, TUP and TUP+ behaviour during fallback and interworking.

It also contains a normative annex on supplementary service support by ISUP Version 1 and an informative bibliography. A figure in Clause 7 shows a functional model for separating ISDN and PSTN traffic and distributing it across carriers.

For implementation work, the document is mainly used to design routing logic, verify signalling interworking, and decide when a call should proceed, fall back, or fail based on the supported bearer and signalling capabilities.

SLOVENSKI STANDARD
01-december-2003
'LJLWDOQRRPUHåMH]LQWHJULUDQLPLVWRULWYDPL,6'1±8VPHUMDQMHNRWSRPRþ
VWRULWYDP,683UD]OLþLFD
Integrated Services Digital Network (ISDN); Routing in support of ISUP Version 1
services
Ta slovenski standard je istoveten z: ETS 300 100 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 100
TELECOMMUNICATION January 1992
STANDARD
Source: ETSI TC-NA Reference: T/N 23-03
ICS: 33.080
ISDN, routing
Key words:
Integrated Services Digital Network (ISDN);
Routing in support of ISUP version 1 services
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
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 1992. All rights reserved.
New presentation - see History box

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ETS 300 100: January 1992
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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ETS 300 100: January 1992
Contents
Foreword.5
1 Scope .7
2 Normative references .7
3 Symbols and abbreviations.8
4 Additions and/or clarifications to CCITT Recommendation E.172 [1].9
4.1 Paragraph 6: Signalling Capability .9
4.2 Annex A to E.172 .9
4.3 Annex B to E.172 .9
5 Additional information on parameters used for routing .9
5.1 Use of the Transmission Medium Requirement parameter .9
5.2 Capability of signalling systems to support various TMRs .10
5.3 Relationship between requested service and TMR values.11
5.4 ISUP preference indicator values for ISDN services .11
5.4.1 General . 11
5.4.2 Services requiring "ISUP Required".12
5.4.3 Services requiring "ISUP Preferred".12
5.4.4 Services requiring "ISUP Not Required".12
6 Interworking requirements for the support of PSTN/IDN services in ISDN .12
6.1 Interworking between TUP/channel associated signalling and ISUP.12
6.1.1 Interworking from TUP/channel associated signalling to ISUP .12
6.1.2 Interworking from ISUP to TUP/channel associated signalling systems .12
6.2 Interworking between TUP+ and ISUP.13
6.2.1 Interworking from TUP+ to ISUP .13
6.2.2 Interworking from ISUP to TUP+ .14
6.3 Interworking impact on supplementary services .15
6.4 Service interworking/intercommunication and fall back.16
6.4.1 Impact on service interworking and intercommunication on routing.16
7 Selection of path/traffic distribution .18
Annex A (normative): Support of supplementary services in ISDN by ISUP version 1.19
Annex B (informative): Bibliography.19
History.20

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ETS 300 100: January 1992
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ETS 300 100: January 1992
Foreword
This European Telecommunication Standard (ETS) has been produced by the Network Aspects (NA)
Technical Committee of the European Telecommunications Standards Institute (ETSI), in co-operation with
the Signalling Protocols and Switching Sub-Committee, and with the T/SF Committee of the Conference of
European Posts and Telecommunications.
This ETS is based on CCITT Recommendation E.172 [1] as given in the CCITT Blue Book, Volume II,
Fascicle II.2, 1988. The requirements of this CCITT Recommendation shall apply together with the
additional elements, and subject to the clarifications identified in this ETS.
CCITT Recommendation I.335 [2], as given in the CCITT Blue Book, Volume II, Fascicle III.8, 1988
describes the use of the ISUP Transmission Medium Requirement for routing.
This ETS has been prepared in support of the ISDN, as defined in ETSI Technical Report ETR 010 "The
ETSI Basic Guide on the European Integrated Services Digital Network (ISDN)", which contains a
complete list of services which the ISDN will provide. This ETS also supports services and capabilities as
specified in ETS 300 121 [3].
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ETS 300 100: January 1992
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ETS 300 100: January 1992
1 Scope
This standard gives guidance on call routing during the implementation of ISDN in Europe, as defined by
the Memorandum of Understanding on the Implementation of the ISDN in Europe in 1992.
It is applicable to the functions required at ISDN international gateways and international transit exchanges
for routing and network planning in order to achieve practical international interconnection of networks.
The relevant CCITT routing recommendations are identified and clarifications and additions to them are
provided where necessary.
This standard is produced in connection with the implementation of ISDN services, using either ISUP
version 1 or CEPT No. 7 TUP+ in the international network. This standard covers the services which are
supported by ISUP version 1.
The following bearer and teleservices are not within the scope of this standard:
- 2 X 64 kbit/s circuit mode bearer service;
- videotex photographic mode;
- computerised communication;
- teleaction;
- audiographic teleconferencing;
- 7 kHz telephony;
- videotelephony.
2 Normative references
This standard incorporates, by dated or undated reference, provisions from other publications. Those
normative references specific to this part are cited at the appropriate places in the text and listed below.
For dated references, subsequent amendments to, or revisions of these publications will apply to this
standard only when incorporated in it by amendment or revision. For undated references the latest edition
of the publication referred to applies.
[1] CCITT Recommendation E.172 (1988): "Call Routing in the ISDN Era".
[2] CCITT Recommendation I.335 (1988): "ISDN Routing Principles".
[3] ETS 300 121: "Integrated Services Digital Network (ISDN); Application of the
ISDN user part of CCITT Signalling System No.7 for international ISDN
interconnections; CCITT Recommendation Q.767 draft edition 3: 1990 -
modified".
[4] CCITT Recommendation I.530 (1988): "Network Interworking between an ISDN
and a PSTN".
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ETS 300 100: January 1992
3 Symbols and abbreviations
BC Bearer Capability
CCITT Comité Consultatif International Telegraphic et Telephonique
CEPT Conférence des Administrations Européenes des Postes et Télécommunications
CLIP Calling Line Identification Presentation
CLIR Calling Line Identification Restriction
COLP Connected Line Identification Presentation
COLR Connected Line Identification Restriction
CUG Closed User Group
DDI Direct Dialling In
ETSI European Telecommunications Standards Institute
IDN Integrated Digital Network
IPI ISUP Preference Indicator
ISDN Integrated Services Digital Network
ISUP ISDN User Part
ITC Information Transfer Capability
MSN Multiple Subscriber Number
PSPDN Public Switched Packet Data Network
PSTN Public Switched Telephone Network
R2 Signalling System R2
SC Signalling Capability
SUB Subaddressing
TMR Transmission Medium Requirement
TP Terminal Portability
TUP Telephone User Part
TUP+ Enhanced Telephone User Part
UUS User-to-User Signalling
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ETS 300 100: January 1992
4 Additions and/or clarifications to CCITT Recommendation E.172 [1]
4.1 Paragraph 6: Signalling Capability
Subclause 5.4 of this standard contains the application of the criteria for setting the IPI parameter for the
implementation of the ISDN in Europe.
In table 3 of the CCITT Recommendation, the cases "64 kbit/s unrestricted" and "ISUP not required" are
characterised by "Not applicable". The conjunction of these two values could nevertheless be used,
according to bilateral agreements, in order to provide an international digital connectivity service (see also
subclause 5.4 of this standard and Note 11 to table 4 of the CCITT Recommendation).
4.2 Annex A to E.172
The information contained in this annex is extended in subclauses 5.1 to 5.3 of this standard, to cover the
implementation of the ISDN in Europe. The interworking situation from PSTN to ISDN is further detailed in
Clause 6 of this standard.
4.3 Annex B to E.172
The application of the criteria defined in this annex to the implementation of the ISDN in Europe is specified
in subclause 5.4 of this standard.
5 Additional information on parameters used for routing
5.1 Use of the Transmission Medium Requirement parameter
The use of the ISUP Transmission Medium Requirement (TMR) parameter for routing is described in:
- CCITT Recommendation E.172 [1], paragraph 5 (h); and
- CCITT Recommendation I.335 [2], paragraphs 4.2.1 (e) and 4.4.4.4.
In addition to the statements made in the above mentioned paragraphs, the following shall apply:
The TMR shall be used for routing in the international network;
The TMR parameter shall be conveyed unchanged in the international network.
For a specific service request, one TMR value shall be used in the international network and across
internetwork boundaries. For its value see subclause 5.3.
It is recommended that national networks use the same TMR values as the international network.
Conversion from the requested service to the TMR value can then be performed in the originating local
exchange. If not done there, then the TMR information must be available from the outgoing international
gateway onwards. It is then forwarded to following exchanges, if possible even up to the destination
exchange.
At transit international exchanges as well as at incoming international gateway exchanges, the TMR shall
be examined for routing purposes, irrespective of the service requested. This does not preclude that
incoming gateway exchanges may need to examine additional information available to determine national
routing.
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ETS 300 100: January 1992
5.2 Capability of signalling systems to support various TMRs
Table 1 indicates, for the different values of TMR, which international signalling systems have the capability
of carrying implicitly or explicitly the TMR information (or request):
Table 1
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¿
‡          ‡         Signalling systems         ‡
‡  Transmission  ˆ˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜·
‡ medium required ‡ CCITT ‡ CEPT  ‡ CCITT ‡ CCITT ‡    ‡ CCITT ‡
‡          ˆ˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜· No.6 ‡  R2  ‡ No.5 ‡
‡          ‡ ISUP ‡ TUP+ ‡  TUP ‡    ‡    ‡    ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜·
‡  64 kbit/s   ‡  V  ‡  V  ‡  V  ‡    ‡    ‡    ‡
‡  unrestricted  ‡    ‡(NOTE 1)‡(NOTE 3)‡(NOTE 2)‡(NOTE 2)‡(NOTE 4)‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜·
‡  3,1 kHz audio  ‡  V  ‡  V  ‡  V  ‡  V  ‡  V  ‡  V  ‡
‡          ‡    ‡(NOTE 1)‡    ‡    ‡    ‡(NOTE 4)‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜·
‡   speech    ‡  V  ‡  V  ‡  V  ‡    ‡    ‡    ‡
‡          ‡    ‡(NOTE 1)‡    ‡(NOTE 2)‡(NOTE 2)‡(NOTE 4)‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜·
‡                                     ‡
‡ V:   The explicit or implicit transfer of the TMR information is   ‡
‡    possible. The signalling system definitely can be used.     ‡
‡                                     ‡
‡ NOTE 1: The TUP+ uses the Information Transfer Capability (ITC) to   ‡
‡     indicate the requested TMR (see subclause 6.2).        ‡
‡                                     ‡
‡ NOTE 2: The explicit transfer of the TMR information is not      ‡
‡     possible. This does not preclude the use of the        ‡
‡     signalling system, if:                     ‡
‡                                     ‡
‡     a) information is made available by other means        ‡
‡       (specialised trunk, particular numbering method); or    ‡
‡                                     ‡
‡     b) the configuration of the network can guarantee the     ‡
‡       provision of the requested TMR; or             ‡
‡                                     ‡
‡     c) there is further enhancement of the signalling systems   ‡
‡       in question.                        ‡
‡                                     ‡
‡ NOTE 3: The TUP provides for a possibility to indicate 64       ‡
‡     kbit/s connectivity.                      ‡
‡                                     ‡
‡ NOTE 4: CCITT Signalling system No. 5 links may not support 64 kbit/s ‡
‡     unrestricted and 3,1 kHz audio bearer service         ‡
‡     because of the splitting function.               ‡
‡                                     ‡
‡     CCITT Signalling system No. 5 does not support all kinds of  ‡
‡     modem operation e.g., V.22bis is not supported. Therefore,   ‡
‡     CCITT Signalling system No. 5 only supports the TMR speech.  ‡
‡                                     ‡
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜�

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ETS 300 100: January 1992
5.3 Relationship between requested service and TMR values
The following table gives TMR values for ISDN services to be used across international and internetwork
boundaries:
Table 2
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¿
‡                 ‡      TMR value      ‡
‡   Requested service      ˆ˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡                 ‡speech ‡ 3,1 kHz ‡  64 kbit/s ‡
‡                 ‡    ‡ audio  ‡ unrestricted ‡
ˆ˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡64 kbit/s unrestricted ‡    ‡     ‡ X      ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡3,1 kHz audio      ‡    ‡  X  ‡       ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜‡
‡     ‡speech         ‡  X  ‡     ‡       ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡ Bearer ‡Packet Mode Case A:   ‡    ‡     ‡ X (NOTE 1) ‡
‡ Service ‡B-Channel        ‡    ‡     ‡       ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Packet Mode Case B:   ‡    ‡     ‡ X      ‡
‡     ‡B-Channel        ‡    ‡     ‡       ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Packet Mode Case B:   ‡    ‡     ‡   (NOTE 2) ‡
‡     ‡D-Channel        ‡    ‡     ‡       ‡
ˆ˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Telephony 3,1 kHz    ‡  X  ‡     ‡       ‡
‡ Tele-  ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡services ‡Telefax Group 4     ‡    ‡     ‡ X      ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Teletex         ‡    ‡     ‡ X      ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡ ISDN Syntax      ‡    ‡     ‡ X      ‡
‡     ‡ Based Videotex     ‡    ‡     ‡       ‡
ˆ˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Telephony        ‡    ‡  X  ‡       ‡
‡PSTN/  ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡ IDN   ‡Facsimile Group 3    ‡    ‡  X  ‡       ‡
‡services ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Voice Band Data     ‡    ‡  X  ‡       ‡
‡     ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡     ‡Digital Connectivity  ‡    ‡     ‡ X      ‡
ˆ˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡ NOTE 1:  If implemented through the use of an on-demand or a   ‡
‡      semipermanent connection basis between the X.25     ‡
‡      terminal and the packet handler.            ‡
‡                                  ‡
‡ NOTE 2:  The packet mode case B D-channel does not use TMR.   ‡
‡                                  ‡
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5.4 ISUP preference indicator values for ISDN service
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