Information technology — Telecommunications and information exchange between systems — Using ECMA-323 (CSTA XML) in a Voice Browser Environment

ISO/IEC TR 18057:2003 illustrates how ECMA-323 can be used in a Voice Browser environment. These concepts illustrated in this TR can be applied to any Voice Browser environment that provides an XML-based read/write messaging interface (i.e. CSTA Service Boundary) that supports asynchronous events from a CSTA conformant communication platform. SALT enabled browsers that implement a ECMA-323 interface for call control using the SALT smex mechanism is an example of a browser with this capability.

Technologies de l'information — Télécommunications et échange d'information entre systèmes — Utilisation de l'ECMA-323 (CSTA XML) dans un environnement de navigateur de voix

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Status
Published
Publication Date
11-Feb-2004
Current Stage
9060 - Close of review
Start Date
19-Dec-2012
Completion Date
19-Dec-2012
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TECHNICAL ISO/IEC
REPORT TR
18057
First edition
2004-02-15
Information technology —
Telecommunications and information
exchange between systems — Using
ECMA-323 (CSTA XML) in a Voice
Browser Environment
Technologies de l'information — Télécommunications et échange
d'information entre systèmes — Utilisation de l'ECMA-323 (CSTA XML)
dans un environnement de navigateur de voix
Reference number
ISO/IEC TR 18057:2004(E)
ISO/IEC 2004
---------------------- Page: 1 ----------------------
ISO/IEC TR 18057:2004(E)
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ii © ISO/IEC 2004 – All rights reserved
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ISO/IEC TR 18057:2004(E)
Contents Page

Foreword............................................................................................................................................................. v

Introduction ....................................................................................................................................................... vi

1 Scope...................................................................................................................................................... 1

2 Normative references........................................................................................................................... 1

3 Brief Overview of ECMA-323................................................................................................................ 2

4 Fundamental Concepts........................................................................................................................ 2

4.1 CSTA Connection.................................................................................................................................. 2

4.2 CSTA Connection State Model ............................................................................................................ 2

4.3 Connection State Transitions for CSTA Calls.................................................................................... 3

4.3.1 Incoming Call......................................................................................................................................... 3

4.3.2 Outgoing Call......................................................................................................................................... 3

5 CSTA Profiles........................................................................................................................................ 4

5.1 Level 1a Voice Browser Profile............................................................................................................ 4

5.1.1 Services.................................................................................................................................................. 4

5.1.2 Events..................................................................................................................................................... 5

5.2 Level 1b Voice Browser Profile ........................................................................................................... 5

5.2.1 Services.................................................................................................................................................. 5

5.2.2 Events..................................................................................................................................................... 5

5.3 Level 2 Voice Browser Profile.............................................................................................................. 6

5.3.1 Services.................................................................................................................................................. 6

5.3.2 Events..................................................................................................................................................... 6

5.4 Basic Telephony Profile....................................................................................................................... 7

5.4.1 Services.................................................................................................................................................. 7

5.4.2 Events..................................................................................................................................................... 7

5.5 Other Features....................................................................................................................................... 7

6 ECMA-323 Illustrative Examples ......................................................................................................... 8

6.1 Discovering the Capabilities of a Telephony Platform...................................................................... 8

6.2 Starting a Monitor (i.e. listening for incoming calls) ......................................................................... 8

6.2.1 Monitor Start – Service Request example .......................................................................................... 8

6.2.2 Monitor Start – Service Response example ....................................................................................... 9

6.3 Notification of an Inbound Call............................................................................................................ 9

6.3.1 Delivered Event example...................................................................................................................... 9

6.4 Answering an Inbound Call................................................................................................................ 10

6.4.1 Answer Call – Service Request example.......................................................................................... 10

6.4.2 Answer Call – Service Response example....................................................................................... 11

6.5 Notification of a Connected Call........................................................................................................ 11

6.5.1 Established Event example................................................................................................................ 11

6.6 Clearing a Connection........................................................................................................................ 12

6.6.1 Clear Connection– Service Request example.................................................................................. 12

6.6.2 Clear Connection – Service Response example.............................................................................. 12

6.7 Notification of a Cleared Connection................................................................................................ 12

6.7.1 Connection Cleared Event example.................................................................................................. 12

6.8 Initiating an Outbound Call ................................................................................................................ 13

6.8.1 Make Call – Service Request example (refer to Profile).................................................................. 13

6.8.2 Make Call – Service Response example........................................................................................... 13

6.9 Outbound Call Event Sequence ........................................................................................................ 14

6.9.1 Originated Event Example.................................................................................................................. 14

6.9.2 Network Reached Event..................................................................................................................... 14

6.9.3 Delivered Event................................................................................................................................... 15

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ISO/IEC TR 18057:2004(E)

6.9.4 Established Event................................................................................................................................16

6.10 Single Step Transfer............................................................................................................................17

6.10.1 Single Step Transfer – Service Request example............................................................................17

6.10.2 Single Step Transfer – Service Response example.........................................................................17

6.11 Notification of a Transferred Connection .........................................................................................17

6.11.1 Transferred Event example................................................................................................................17

6.12 Deflect...................................................................................................................................................18

6.12.1 Deflect – Service Request example...................................................................................................18

6.12.2 Deflect – Service Response example................................................................................................19

6.13 Notification of a Diverted Connection...............................................................................................19

6.13.1 Diverted Event example......................................................................................................................19

6.14 Single Step Conference......................................................................................................................20

6.14.1 Single Step Conference – Service Request example ......................................................................20

6.14.2 Single Step Conference – Service Response example ...................................................................20

6.15 Notification of an Party Added to a call ............................................................................................21

6.15.1 Conferenced Event example ..............................................................................................................21

6.16 Failure Response example.................................................................................................................22

7 SALT/CSTA XML Programming Example .........................................................................................22

8 CCXML/CSTA XML Programming Example......................................................................................26

9 CSTA Call Control Features ...............................................................................................................28

9.1 Services................................................................................................................................................29

9.2 Events...................................................................................................................................................30

iv © ISO/IEC 2004 – All rights reserved
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ISO/IEC TR 18057:2004(E)
Foreword

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical

Commission) form the specialized system for worldwide standardization. National bodies that are members of

ISO or IEC participate in the development of International Standards through technical committees

established by the respective organization to deal with particular fields of technical activity. ISO and IEC

technical committees collaborate in fields of mutual interest. Other international organizations, governmental

and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information

technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of the joint technical committee is to prepare International Standards. Draft International

Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as

an International Standard requires approval by at least 75 % of the national bodies casting a vote.

In exceptional circumstances, the joint technical committee may propose the publication of a Technical Report

of one of the following types:

— type 1, when the required support cannot be obtained for the publication of an International Standard,

despite repeated efforts;

— type 2, when the subject is still under technical development or where for any other reason there is the

future but not immediate possibility of an agreement on an International Standard;

— type 3, when the joint technical committee has collected data of a different kind from that which is

normally published as an International Standard (“state of the art”, for example).

Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether

they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to

be reviewed until the data they provide are considered to be no longer valid or useful.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.

ISO/IEC TR 18057, which is a Technical Report of type 3, was prepared by Joint Technical Committee

ISO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecommunications and information exchange

between systems.

ISO/IEC 18057 was prepared by ECMA (as ECMA TR/85) and was adopted, under a special “fast-track

procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its approval

by national bodies of ISO and IEC.
© ISO/IEC 2004 – All rights reserved v
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ISO/IEC TR 18057:2004(E)
Introduction

This Technical Report illustrates how CSTA XML (ECMA-323) can be used in a Voice Browser environment.

This TR is part of a suite of ECMA CSTA Phase III Standards and Technical Reports.

All of the Standards and Technical Reports in this Suite are based upon the practical experience of ECMA

member companies and each one represents a pragmatic and widely based consensus.
vi © ISO/IEC 2004 – All rights reserved
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TECHNICAL REPORT ISO/IEC TR 18057:2004(E)
Information technology — Telecommunications and information
exchange between systems — Using ECMA-323 (CSTA XML) in
a Voice Browser Environment
1 Scope

Services for Computer Supported Telecommunications Applications are defined by Standard ECMA-269 and

the XML Protocol for those services are defined by Standard ECMA-323.

In many cases, applications require only a small subset of the features standardized in CSTA. In a voice

browser environment, processing speech (not call control) is usually the major focus of the application. For

example, from a CSTA feature perspective, an application may simply need to answer an incoming call and

then later clear it. As these speech-centric applications evolve they can use additional, more advanced,

features standardized by CSTA that are provided by CSTA-conformant communications platforms.

Since ECMA-269 and ECMA-323 are relatively large standards (combined over 1100 pages), it is a challenge

for application developers without prior knowledge of the CSTA standards to know where to find basic

concepts that they need to understand in order to implement basic CSTA features.

This TR illustrates how ECMA-323 can be used in a Voice Browser environment. These concepts illustrated in

this TR can be applied to any Voice Browser environment that provides an XML-based read/write messaging

interface (i.e. CSTA Service Boundary) that supports asynchronous events from a CSTA conformant

communication platform. SALT enabled browsers that implement a ECMA-323 interface for call control using

the SALT smex mechanism is an example of a browser with this capability.

Throughout this TR the term “ECMA-323 enabled voice browser” is used, in a generic sense, to refer to

browser implementation that support a CSTA conformant ECMA-323 interface.

Examples are provided that show how ECMA-323 can be used in several different environments such as

SALT-enabled browsers and CCXML.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

This TR provides informative examples of how to use ECMA-323 in a Voice Browser environment. The

following ECMA Standards should be used as the definitive references for CSTA:

ECMA-269:2002, Services for Computer Supported Telecommunications Applications (CSTA) Phase III

(ISO/IEC 18051:2003)

ECMA-323:2002, XML Protocol for Computer Supported Telecommunications Applications (CSTA) Phase III

(ISO/IEC 18056:2003)

ECMA CSTA Standards can be used for call control in many different environments. The following references

provide additional information on using the ECMA CSTA Standards in different environments:

SALT Speech language Application Language Tags 1.0 Specification (SALT), SALT Forum, 15 July 2002,

(http://www.saltforum.org).
© ISO/IEC 2004 – All rights reserved 1
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ISO/IEC TR 18057:2004(E)

CCXML Voice Browser Call Control: CCXML Version 1.0 - W3C Working Draft, W3C, 11 October 2002,

(http://www.w3c.org/TR/ccxml/).
3 Brief Overview of ECMA-323
ECMA-323 consists of a set of XML Schemas based upon the W3C XML Schema Language

Recommendation. The Standard includes schemas for many categories of services defined in ECMA-269

(Services for Computer Supported Telecommunications Applications (CSTA) Phase III).

Call control is just one category of services in ECMA-323. Examples of other categories of services are:

capability exchange (feature discovery) services, call routing services, services to control a device (e.g.

message waiting, writing to display, forwarding settings), and many others.

CSTA provides a protocol independent abstraction layer for applications. It provides a consistent, standards-

based messaging interface that can be used with basic 1 party call control based platforms as well as more

rd st

complex 3 party call control (CTI) platforms, or a combination of both (1 party call control with some

additional 3 party call control features).

CSTA modelling and concepts are also compatible with many procedural and object models such as the SALT

CallControl object (chapter 3 of the SALT specification).
4 Fundamental Concepts

This section introduces some informative modelling concepts that are useful to illustrate how ECMA-323

enabled voice browsers can use ECMA-323 messages. The actual ECMA CSTA standards should be used

for the definitive descriptions.
4.1 CSTA Connection

CSTA call control services are applied to CSTA connections. A CSTA connection refers to a relationship

between a call and a telephony endpoint. A CSTA connection is referenced via a CSTA connection identifier.

A CSTA connection identifier consists of a call identifier and a device (endpoint) identifier.

In a typical 1 party call control implementation, a voice browser application manipulates only the CSTA

connection directly associated with the voice browser platform. However, other call control implementations

may also provide application control of other endpoints in the call using CSTA services (via 3 party call

control, for example). A device identifier is included in a CSTA connection identifier to allow any endpoint to be

addressed by a voice browser application.
4.2 CSTA Connection State Model

A ECMA-323 enabled voice browser application is informed of connection state transitions (via ECMA-323 call

control events) by placing a monitor on a telephony endpoint via an associated address (e.g. this is how an

application “listens” for incoming calls).

Each CSTA connection in a call is associated with a connection state. CSTA specifies a connection state

model (see ECMA-269, Figure 6-19) that consists of the following connection states:

• Alerting –Indicates an incoming call at an endpoint. Typically the connection may be ringing or it may be in

a pre-alerting (e.g. offered) condition.

• Connected – Indicates that a connection is actively participating in a call. This connection state can be the

result of an incoming or outgoing call.

• Failed – Indicates that call progression has stalled. Typically this could represent that an outgoing call

attempt that encountered a busy endpoint.
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ISO/IEC TR 18057:2004(E)

• Held – Indicates that an endpoint is no longer actively participating in a call. For implementations that

support multiple calls per endpoint (i.e. line), a connection could be Held while the line is used to place

another call (consultation transfer on an analog line, for example).

• Initiated – A transient state, usually indicating that the endpoint is initiating a service (e.g. dialtone).

• Null – There is no relationship between the call and the endpoint.

• Queued – Indicates that the call is temporarily suspended at a device (e.g. call has been parked, camped

on).
The CSTA Connection State is provided in ECMA-323 events.
4.3 Connection State Transitions for CSTA Calls
4.3.1 Incoming Call

The following figure illustrates the CSTA events for an incoming call. The connection state of endpoint on the

voice browser platform (called connection) is indicated in parenthesis.

• Delivered Event (Alerting) – Indicates call is alerting. Calls that are “auto-answered” do not sent this event.

A CSTA Answer Call service can be used to answer the call. This results in an Established event.

• Established Event (Connected) – indicates call has been answered. Media path has been established.

The CSTA Clear Connection service can be used to clear the call. A Connection Cleared event is

generated as the result of the Clear Connection service.

• Connection Cleared Event (Null) – indicates connection has cleared. This can be the result of the Clear

Connection service or as the result of any party clearing from the call.
Incoming Call is Call is
Delivered Established Connection
call arrives answered cleared
Event Event Cleared Event
4.3.2 Outgoing Call

The following figure illustrates the CSTA events for an outgoing call. The connection state of the endpoint on

the Voice Browser platform (originating connection) is indicated in parenthesis. This sequence could be the

result of a CSTA Make Call service.

• Originated Event (Connected) – Indicates that the originating connection (an endpoint on the voice

browser platform) is connected.
• Delivered Event (Connected) – Indicates the call is alerting the called party.

• Established Event (Connected) – indicates the called party has answered the call. Media path has been

established.
• Connection Cleared Event (Null) – indicates connection has cleared.
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ISO/IEC TR 18057:2004(E)
called party called called
Delivered Established Connection
Originated
is alerted party party
Event Event Event Cleared Event
5 CSTA Profiles

Since many CSTA features are optional, and to enhance application portability across different CSTA

implementations, CSTA standards require a minimal subset of functionality as conformance criteria.

ECMA-269 specifies a set of Profiles. At least one profile is required to be supported. The following profiles

most closely match the call control services and events needed by a Voice Browser application.

• Level 1a Voice Browser Profile (added in ECMA-269 5 edition) – provides support for answering an

incoming call, clearing, and moving the call to another endpoint using the Single Step Transfer Call

service. The Get Switching Function Capabilities Service is not required to be supported in this profile.

• Level 1b Voice Browser Profile (added in ECMA-269 5 edition) - provides support for answering an

incoming call, clearing, and moving the call to another endpoint using the Deflect Call service. The Get

Switching Function Capabilities Service is not required to be supported in this profile.

• Level 2 Voice Browser Profile (added in ECMA-269 5 edition) – provides support for making a call in

addition to the services and events required in either the Level1a Voice Browser Profile of the Level 1b

Voice Browser Profile. The Get Switching Function Capabilities Service is required to be supported in this

profile.

• Basic Telephony Profile –provides support for answering an incoming call, creating an outgoing call, and

clearing the call. The Get Switching Function Capabilities Service is required to be supported in this profile.

NOTE Telephony platforms that interface with networks and/or endpoints that do not expose the underlying

network/device signalling are not expected to provide all of these CSTA events. For example, if the telephony network

does not provide a busy indication, the Failed event is not required.
5.1 Level 1a Voice Browser Profile
5.1.1 Services
The following CSTA services are included in the Level 1a Voice Browser Profile:

• Answer call – Answers an alerting call. In a voice browser, the answering device is an endpoint on the

platform.

• Clear Connection – Clears a connection. In a voice browser environment, the clearing device is an

endpoint on the voice browser platform.

• Single Step Transfer (of a connected call) – Transfers a call to another endpoint. In a voice browser

environment, the transferring device is an endpoint on the voice browser platform and is no longer

involved with the call after the single step transfer service is completed.

• Monitor Start – Establishes a device-type monitor on an endpoint. In a voice browser environment, the

monitored device is an endpoint on the voice browser platform.
• Monitor Stop – Terminates an existing monitor.
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ISO/IEC TR 18057:2004(E)
5.1.2 Events
The following CSTA events are included in the Level 1a Voice Browser Profile:
• Connection Cleared – Indicates that an endpoint has disconnected from a call.
• Delivered – Indicates that a call is alerting an endpoint.

• Established – Indicates that an endpoint has answered or been connected to a call.

• Failed – Indicates that a call cannot be completed (e.g. call has encountered a busy endpoint).

• Transferred – Indicates that an existing call has been transferred from an endpoint (on the voice browser

platform) to another endpoint and has been disconnected from the call. This implies that the transferring

device connection state is Null – no Connection Cleared event is generated for the transferring device

after the Transferred event.
5.2 Level 1b Voice Browser Profile
5.2.1 Services
The following CSTA services are included in the Level 1b Voice Browser Profile:

• Answer call – Answers an alerting call. In a voice browser, the answering device is an endpoint on the

platform.

• Clear Connection – Clears a connection. In a voice browser environment, the clearing device is an

endpoint on the voice browser platform.

• Deflect (of a connected call) – Moves a connection away from the deflecting device. In a voice browser

environment, the deflecting device is an endpoint on the voice browser platform and is no longer involved

with the call after the Deflect Call service is completed.

• Monitor Start – Establishes a device-type monitor on an endpoint. In a voice browser environment, the

monitored device is an endpoint on the voice browser platform.
• Monitor Stop – Terminates an existing monitor.
5.2.2 Events
The follow
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