SIST EN 300 368 V1.2.2:2005
(Main)Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary service; Functional capabilities and information flows
General Information
- Abstract
To reflect changes in service description and in DSS1 protocol: 1) Remove requirement for one call to be placed on hold. TD16 to SPS1 Prague (03/98) refers and gives proposed changes; 2) Reflect changes in Q.82.7. Unnumbered TD to Prague refers. Supporting organizations: SGCS Ltd., GTP Ltd., KPN, BT.
- Status
- Published
- Publication Date
- 31-Mar-2005
- Technical Committee
- SPN - Services and Protocols for Networks
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 01-Apr-2005
- Due Date
- 01-Apr-2005
- Completion Date
- 01-Apr-2005
Overview
SIST EN 300 368 V1.2.2:2005 specifies the stage two functional capabilities and information flows for the Explicit Call Transfer (ECT) supplementary service within the Integrated Services Digital Network (ISDN). Developed by SI Slovenski inštitut za standardizacijo (SIST) and harmonized with the European EN 300 368 standard, this document provides a structured approach to supporting ECT functionality as offered by European public telecommunications operators. The standard responds to evolving network requirements, particularly in DSS1 protocol interactions, and aligns its methodology with recognized ITU-T recommendations for service characterization and signaling protocols.
ECT is a valuable ISDN supplementary service enabling users who have two calls (incoming or outgoing) to connect the other call participants together, effectively transferring the call. This capability is essential for the efficient handling of communications in both enterprise and public network environments.
Key Topics
- Service Architecture: Defines functional entities and their roles in supporting ECT, focusing on transfer-by-join while addressing interworking with transfer-by-rerouteing in private networks.
- Information Flows: Details the signaling and data exchange between relevant ISDN entities to support explicit call transfer operations, including initiation, execution, and completion.
- State Conditions: Explains valid call states for invoking ECT, clarifying when transfers can be performed depending on call activity (e.g., active, held, alerting).
- Loop Prevention: Provides guidance on optional loop test procedures to avoid service logic errors in complex call transfer scenarios.
- Protocol Alignment: Reflects changes in DSS1 and incorporates updates consistent with ITU-T Recommendations (e.g., Q.65 methodology).
- Conformance and Interworking: Outlines interoperability with basic circuit-switched services and identifies scope limitations regarding private ISDN and non-ISDN environments.
Applications
The ECT supplementary service is highly relevant for a variety of ISDN applications, especially where streamlined call handling and user-driven call management are required:
- Business Telephony Systems: Enables receptionists, agents, and employees to transfer calls efficiently without dropping participants, improving workflow and customer experience.
- Contact Centers: Facilitates agent-to-agent or agent-to-supervisor call transfers, supporting seamless customer support operations.
- Public Network Services: Allows end-users to manage multiple simultaneous calls, enhancing call control flexibility for subscribers.
- Unified Communications: Supports integration into broader unified communications solutions relying on ISDN infrastructure.
By ensuring consistent implementation of ECT across equipment and networks, SIST EN 300 368 V1.2.2:2005 helps operators and manufacturers provide reliable supplementary services, maintain interoperability, and support advanced telephony features expected in modern digital communications.
Related Standards
For organizations and professionals working with ECT and ISDN services, the following standards are directly related:
- EN 300 367: Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary service; Service description (Stage 1)
- EN 300 369-1: Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary service; DSS1 protocol specification (Stage 3)
- ITU-T Recommendation I.112: Definitions for ISDN vocabulary
- ITU-T Recommendation Q.65: Functional methodology for services and network capabilities
- ITU-T Recommendation Q.71: ISDN circuit-mode switched bearer services
These standards ensure a harmonized approach to ISDN supplementary service design, specification, and implementation, supporting network evolution and consistent service quality for users across Europe.
Keywords: ISDN, Explicit Call Transfer, ECT, supplementary service, functional capabilities, information flows, DSS1, telecommunications standards, call transfer, network interoperability, digital telephony.
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Frequently Asked Questions
SIST EN 300 368 V1.2.2:2005 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary service; Functional capabilities and information flows". This standard covers: To reflect changes in service description and in DSS1 protocol: 1) Remove requirement for one call to be placed on hold. TD16 to SPS1 Prague (03/98) refers and gives proposed changes; 2) Reflect changes in Q.82.7. Unnumbered TD to Prague refers. Supporting organizations: SGCS Ltd., GTP Ltd., KPN, BT.
To reflect changes in service description and in DSS1 protocol: 1) Remove requirement for one call to be placed on hold. TD16 to SPS1 Prague (03/98) refers and gives proposed changes; 2) Reflect changes in Q.82.7. Unnumbered TD to Prague refers. Supporting organizations: SGCS Ltd., GTP Ltd., KPN, BT.
SIST EN 300 368 V1.2.2:2005 is classified under the following ICS (International Classification for Standards) categories: 33.080 - Integrated Services Digital Network (ISDN). The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 300 368 V1.2.2:2005 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2005
Digitalno omrežje z integriranimi storitvami (ISDN) - Dopolnilna storitev:
nedvoumna predaja klica (ECT) - Funkcijske zmožnosti in informacijski tokovi
Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT) supplementary
service; Functional capabilities and information flows
Ta slovenski standard je istoveten z: EN 300 368 Version 1.2.2
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.
EN 300 368 V1.2.2 (1998-12)
European Standard (Telecommunications series)
Integrated Services Digital Network (ISDN);
Explicit Call Transfer (ECT) supplementary service;
Functional capabilities and information flows
2 EN 300 368 V1.2.2 (1998-12)
Reference
REN/SPS-01060 (3eo00ipc.PDF)
Keywords
ISDN, supplementary service, ECT, ISUP,
stage 2
ETSI
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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 1998.
All rights reserved.
ETSI
3 EN 300 368 V1.2.2 (1998-12)
Contents
Intellectual Property Rights. 5
Foreword. 5
1 Scope . 6
2 Normative references. 6
3 Definitions. 7
4 Abbreviations.7
5 Description . 8
6 Derivation of the functional model. 8
6.1 Functional model description.8
6.2 Description of the FEs .8
6.3 Relationship with a basic service .9
7 Information flows. 9
7.1 Information flow diagrams.9
7.2 Definition of the individual information flows.12
7.2.1 Relationship rq.12
7.2.1A Contents of TRANSFER INVOKE.12
7.2.2 Relationship rr.12
7.2.2A Contents of TRANSFER INVOKE.12
7.2.3 Relationship rs1 .13
7.2.3.1 Contents of TRANSFER COMPLETE .13
7.2.3.2 Contents of TRANSFER ACTIVE.13
7.2.3.3 Contents of LOOP TEST .13
7.2.3.4 Contents of LOOP TEST REJECT .13
7.2.4 Relationship rs2 .13
7.2.4.1 Contents of TRANSFER COMPLETE .13
7.2.4.2 Contents of TRANSFER ACTIVE.14
7.2.4.3 Contents of TERMINAL DETAILS.14
7.2.4.4 Contents of LOOP TEST .14
7.2.4.5 Contents of LOOP TEST REJECT .14
7.2.5 Relationship rt.14
7.2.5.1 Contents of TRANSFER INFORM.14
7.2.5.2 Contents of TERMINAL DETAILS.15
7.2.6 Relationship ru .15
7.2.6A Contents of TERMINAL DETAILS.15
8 SDL diagrams for FEs. 16
8.1 FE1 .16
8.2 FE2 .18
8.3 FE3 .19
8.4 FE4 .23
8.5 FE5 .26
8.6 FE6 .29
9 Functional Entity Actions (FEAs) . 30
9.1 FEAs of FE1 .30
9.2 FEAs of FE2 .30
9.3 FEAs of FE3 .30
9.4 FEAs of FE4 .31
9.5 FEAs of FE5 .31
9.6 FEAs of FE6 .32
ETSI
4 EN 300 368 V1.2.2 (1998-12)
10 Allocation of FEs to physical locations . 32
History. 34
ETSI
5 EN 300 368 V1.2.2 (1998-12)
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
SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect
of ETSI standards", which is available free of charge from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (http://www.etsi.org/ipr).
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 SR 000 314 (or the updates on the ETSI Web server) which
are, or may be, or may become, essential to the present document.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Signalling
Protocols and Switching (SPS).
In accordance with CCITT Recommendation I.130, the following three level structure is used to describe the
supplementary telecommunication services as provided by European public telecommunications operators under the
pan-European Integrated Services Digital Network (ISDN):
- Stage 1: is an overall service description, from the user's standpoint;
- Stage 2: identifies the functional capabilities and information flows needed to support the service described in
stage 1; and
- Stage 3: defines the signalling system protocols and switching functions needed to implement the service described
in stage 1.
The present document details the stage 2 aspects (functional capabilities and information flows) needed to support the
Explicit Call Transfer (ECT) supplementary service. The stage 1 and stage 3 aspects are detailed in EN 300 367 [6] and
EN 300 369-1 [7], respectively.
National transposition dates
Date of adoption of this EN: 11 December 1998
Date of latest announcement of this EN (doa): 31 March 1999
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 30 September 1999
Date of withdrawal of any conflicting National Standard (dow): 30 September 1999
ETSI
6 EN 300 368 V1.2.2 (1998-12)
1 Scope
The present document defines the stage two description of the Explicit Call Transfer (ECT) supplementary service for the
pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications
operators. Stage two identifies the functional capabilities and the information flows needed to support the service
description as described in stage one. The stage two description also identifies user operations not directly associated
with a call (see CCITT Recommendation 1.130 [2]).
The present document is specified according to the methodology specified in CCITT Recommendation Q.65 [3].
The present document does not formally describe the relationship between this supplementary service and the basic call,
but where possible this information is included for guidance.
In addition the present document does not specify the requirements where the service is provided to the user via a private
ISDN. The present document does not specify the requirements for the allocation of defined Functional Entities (FEs)
within a private ISDN; it does, however, define which functional entities may be allocated to a private ISDN.
The present document does not specify the additional requirements where the service is provided to the user via a
telecommunications network that is not an ISDN.
The ECT supplementary service enables a user who has two calls, each of which can be an incoming or an outgoing call,
to connect the other users in the two calls.
The ECT supplementary service is applicable to all circuit-switched telecommunication services.
The present document is applicable to the stage three standards for the ISDN ECT supplementary service. The term "stage
three" is also defined in CCITT Recommendation 1.130 [2]. Where the text indicates the status of a requirement, i.e. as
strict command or prohibition, as authorization leaving freedom, as a capability or possibility, this shall be reflected in
the text of the relevant stage two and stage three standards.
Furthermore, conformance to the present document is met by conforming to the stage three standards with the field of
application appropriate to the equipment being implemented. Therefore, no method of testing is provided for the present
document.
2 Normative 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, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, subsequent revisions do apply.
• A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same
number.
[1] ITU-T Recommendation I.112 (1993): "Vocabulary of terms for ISDNs".
[2] CCITT Recommendation I.130 (1988): "Method for the characterization of telecommunication
services supported by an ISDN and network capabilities of an ISDN".
[3] ITU-T Recommendation Q.65 (06/97): "The unified functional methodology for the characterization
of services and network capabilities".
[4] ITU-T Recommendation Q.71 (03/93): "ISDN Circuit mode switched bearer services".
[5] CCITT Recommendation Z.100 (1988): "Specification and Description Language (SDL)".
ETSI
7 EN 300 368 V1.2.2 (1998-12)
[6] EN 300 367: "Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT)
supplementary service; Service description".
[7] EN 300 369-1: Integrated Services Digital Network (ISDN); Explicit Call Transfer (ECT)
supplementary service; Digital Subscriber Signalling System No. one (DSS1) protocol; Part 1:
Protocol specification".
3 Definitions
For the purposes of the present document, the following definitions apply:
Integrated Services Digital Network (ISDN): See ITU-T Recommendation I.112 [1], definition 308.
primary call: One of user A's (answered) calls.
secondary call: The other user A call (answered or alerting).
service; telecommunication service: See ITU-T Recommendation I.112 [1], definition 201.
transfer by join: The effecting of transfer by joining together the primary and secondary calls at user A's local exchange.
transfer by rerouteing: The effecting of transfer by establishing a new connection to replace the primary and secondary
calls.
user A: The served user, i.e. the user requesting the ECT supplementary service.
user B: The other user in user A's primary call.
user C: The other user in user A's secondary call.
4 Abbreviations
For the purposes of the present document, the following abbreviations apply:
CC Call Control
CCA Call Control Agent
ECT Explicit Call Transfer
FE Functional Entity
FEA Functional Entity Action
ISDN Integrated Services Digital Network
LE Local Exchange
PTNX Private Telecommunication Network eXchange
SDL Specification and Description Language
TE Terminal Equipment
ETSI
8 EN 300 368 V1.2.2 (1998-12)
5 Description
This stage two supports only one variant of the ECT supplementary service, that of transfer by join. The functional model
supports interworking with transfer by rerouteing, which may occur within a private network but involving users of a
public network.
Table 1 shows the states for the invocation of the ECT supplementary service.
Table 1: States for invocation of ECT
Secondary call Primary call
Active, held Active, idle
Active, held Alerting, idle (note)
Active, idle Alerting, held (note)
Active, idle Active, idle
Active, idle Alerting, idle (note)
NOTE: Only applicable for an outgoing call.
The procedures are currently restricted to basic telecommunication services involving a single 64 kbit/s connection. The
present document is not applicable to a video telephony call involving two 64 kbit/s connections.
6 Derivation of the functional model
6.1 Functional model description
The functional model for the ECT supplementary service is shown in figure 1.
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6.2 Description of the FEs
The FEs required by the ECT supplementary service in addition to those of basic call are as follows:
FE1: Transfer invoke entity;
FE2: Transfer validate entity;
FE3: Transfer execute entity;
FE4: Transfer screen entity;
FE5: Transfer complete receive entity;
FE6: Transfer inform receive entity.
ETSI
9 EN 300 368 V1.2.2 (1998-12)
6.3 Relationship with a basic service
The relationship with a basic service is as shown in figure 2.
NOTE: The basic call model is defined in CCITT Recommendation Q.71 [4], subclause 2.1, with the exception that
r1 represents an outgoing call relationship from a Call Control Agent (CCA) and r3 represents an incoming
call relationship to a CCA.
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7 Information flows
7.1 Information flow diagrams
The information flow diagrams assume the existence of a primary call and a secondary call and that both calls are
maintained until the completion of the transfer. Clearing of the primary and secondary calls with respect to the served user
is not shown as this uses basic call information flows only. Similarly any information flows concerned with holding and
retrieving the primary and secondary calls are outside the scope of the present document.
The TERMINAL DETAILS information flow may occur between both FE6s. Where there is no information to be sent at
all, the information flow is not present in either direction. The information flow is only shown in one direction in figure 3
for reasons of clarity.
The TRANSFER ACTIVE information flow will only occur in the case of an alerting transfer where the alerting user
subsequently answers. In such a case, a TERMINAL DETAILS information flow from user B's FE6 may also occur as a
result of receiving the second TRANSFER INFORM indication.
ETSI
10 EN 300 368 V1.2.2 (1998-12)
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NOTE: If the optional procedures for preventing loops are provided, the information flow shown in figure 4 occurs at this point, before proceeding with the rest of the information
flow shown in this figure.
Figure 3 (sheet 1 of 2): Successful call transfer
ETSI
11 EN 300 368 V1.2.2 (1998-12)
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