SIST-TP ETSI/TR 102 171 V1.1.1:2005

SLOVENSKI STANDARD
SIST-TP ETSI/TR 102 171 V1.1.1:2005
01-marec-2005
Uporaba ECMA-323 (CSTA XML) v okolju govornega brskalnika
Using ECMA-323 (CSTA XML) in a Voice Browser Environment
Ta slovenski standard je istoveten z: TR 102 171 Version 1.1.1
ICS:
33.030 Telekomunikacijske Telecommunication services.
uporabniške rešitve Applications
SIST-TP ETSI/TR 102 171 V1.1.1:2005 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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Intellectual Property Rights................................................................................................................................5

Foreword.............................................................................................................................................................5

Brief History.......................................................................................................................................................5

1 Scope........................................................................................................................................................6

2 References................................................................................................................................................6

3 Brief Overview of ECMA-323.................................................................................................................6

4 Fundamental Concepts.............................................................................................................................7

4.1 CSTA Connection..............................................................................................................................................7

4.2 CSTA Connection State Model..........................................................................................................................7

4.3 Connection State Transitions for CSTA Calls....................................................................................................8

4.3.1 Incoming Call...............................................................................................................................................8

4.3.2 Outgoing Call................................................................................................................................................8

5 CSTA Profiles..........................................................................................................................................8

5.1 Level 1a Voice Browser Profile .........................................................................................................................9

5.1.1 Services.........................................................................................................................................................9

5.1.2 Events...........................................................................................................................................................9

5.2 Level 1b Voice Browser Profile .........................................................................................................................9

5.2.1 Services.........................................................................................................................................................9

5.2.2 Events.........................................................................................................................................................10

5.3 Level 2 Voice Browser Profile.........................................................................................................................10

5.3.1 Services.......................................................................................................................................................10

5.3.2 Events.........................................................................................................................................................10

5.4 Basic Telephony Profile ...................................................................................................................................11

5.4.1 Services.......................................................................................................................................................11

5.4.2 Events.........................................................................................................................................................11

5.5 Other Features..................................................................................................................................................12

6 ECMA-323 Illustrative Examples..........................................................................................................12

6.1 Discovering the Capabilities of a Telephony Platform.....................................................................................12

6.2 Starting a Monitor (i.e. listening for incoming calls) .......................................................................................12

6.2.1 Monitor Start - Service Request example ...................................................................................................12

6.2.2 Monitor Start - Service Response example.................................................................................................13

6.3 Notification of an Inbound Call........................................................................................................................13

6.3.1 Delivered Event example............................................................................................................................13

6.4 Answering an Inbound Call..............................................................................................................................14

6.4.1 Answer Call - Service Request example.....................................................................................................14

6.4.2 Answer Call - Service Response example ..................................................................................................15

6.5 Notification of a Connected Call......................................................................................................................15

6.5.1 Established Event example .........................................................................................................................15

6.6 Clearing a Connection......................................................................................................................................15

6.6.1 Clear Connection - Service Request example.............................................................................................16

6.6.2 Clear Connection - Service Response example ..........................................................................................16

6.7 Notification of a Cleared Connection...............................................................................................................16

6.7.1 Connection Cleared Event example............................................................................................................16

6.8 Initiating an Outbound Call..............................................................................................................................17

6.8.1 Make Call - Service Request example (refer to Profile) .............................................................................17

6.8.2 Make Call - Service Response example......................................................................................................17

6.9 Outbound Call Event Sequence........................................................................................................................17

6.9.1 Originated Event Example..........................................................................................................................17

6.9.2 Network Reached Event .............................................................................................................................18

6.9.3 Delivered Event..........................................................................................................................................19

6.9.4 Established Event........................................................................................................................................20

6.10 Single Step Transfer .........................................................................................................................................20

6.10.1 Single Step Transfer - Service Request example ........................................................................................20

6.10.2 Single Step Transfer - Service Response example......................................................................................20

6.11 Notification of a Transferred Connection.........................................................................................................20

6.11.1 Transferred Event example.........................................................................................................................20

6.12 Deflect..............................................................................................................................................................21

6.12.1 Deflect - Service Request example .............................................................................................................21

6.12.2 Deflect - Service Response example...........................................................................................................22

6.13 Notification of a Diverted Connection .............................................................................................................22

6.13.1 Diverted Event example..............................................................................................................................22

6.14 Single Step Conference ....................................................................................................................................22

6.14.1 Single Step Conference - Service Request example ...................................................................................22

6.14.2 Single Step Conference - Service Response example.................................................................................23

6.15 Notification of an Party Added to a call...........................................................................................................23

6.15.1 Conferenced Event example .......................................................................................................................23

6.16 Failure Response example................................................................................................................................24

7 SALT/CSTA XML Programming Example...........................................................................................25

8 CCXML/CSTA XML Programming Example ......................................................................................29

9 CSTA Call Control Features ..................................................................................................................32

9.1 Services............................................................................................................................................................32

9.2 Events...............................................................................................................................................................33

History ..............................................................................................................................................................35

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This Technical Report (TR) has been produced by ECMA on behalf of its members and those of the European

The present document illustrates how CSTA XML (ECMA-323) can be used in a Voice Browser environment. The

present document 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

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

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

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

The present document illustrates how ECMA-323 can be used in a Voice Browser environment. These concepts

illustrated in the present document 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

Throughout the present document the term "ECMA-323 enabled voice browser" is used, in a generic sense, to refer to

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

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

ECMA-269: "Services for Computer Supported Telecommunications Applications (CSTA) Phase III".

ECMA-323: "XMLProtocol for Computer Supported Telecommunications Applications (CSTA) Phase III".

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 Application Language Tags Specification Version 1.0", SALT Forum, 15 July 2002.

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

ECMA-323 consists of a set of XML Schemas based upon the W3C XML Schema Language Recommendation. The

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

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 complex 3 party

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

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

This clause 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

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

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

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

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

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

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

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

• 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

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

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

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

• 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

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

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

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

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

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.

• 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

• 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

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

• 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

• 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

• 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

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

• Diverted: Indicates that the endpoint (on the voice browser platform) has redirected a call to another 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).

In this profile, a CSTA implementation is required to provide its capabilities to applications via the ECMA-323 Get

Switching Function Capabilities service. The capabilities include the list of ECMA-323 services and events supported

by a telephony platform and the various types of behaviour options supported by an implementation (the profile(s)

supported, the types of digits that are allowed in the dialling string for an outbound call, etc.). Many of the parameters