ISO/TR 16056-2:2004

TECHNICAL ISO/TR
REPORT 16056-2
First edition
2004-07-01

Health informatics — Interoperability of
telehealth systems and networks —
Part 2:
Real-time systems
Informatique de santé — Interopérabilité des systèmes et des réseaux
de télésanté —
Partie 2: Systèmes en temps réel



Reference number
ISO/TR 16056-2:2004(E)
©
ISO 2004

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ISO/TR 16056-2:2004(E)
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ISO TR 16056-2:2004(E)

Contents Page
Foreword . v
Introduction. vi
1 Scope . 1
2 Normative References. 1
3 Terms and definitions . 2
4 Abbreviations . 12
5 Multimedia Conferencing Standards . 13
5.1 General . 13
5.2 H.320 recommendations . 16
5.3 H.321 and H.310 Recommendations . 17
5.4 H.323 Recommendations . 19
5.4.1 H.323 Terminals . 19
5.4.2 Gateways. 21
5.4.3 Gatekeeper . 21
5.4.4 Multipoint control unit . 21
5.5 H.324 Recommendations . 22
5.6 T.120 Recommendations . 23
5.6.1 T120 Overview. 23
5.6.2 T.120 Layer composition. 23
5.6.3 T.120 Interoperability.24
6 Telehealth applications . 24
6.1 General . 24
6.2 Telelearning . 25
6.3 Teleconsultation . 26
7 Interoperability issues . 28
7.1 General . 28
7.2 Standard-related sources of interoperability issues. 28
7.2.1 Loose adaptation of previous protocols. 29
7.2.2 Loosely defined encoding and decoding methods. 29
7.2.3 Inconsistent definition of mandatory/optional requirements. 29
7.2.4 Gaps in the recommendations. 29
7.2.5 No specifications for data encoding in the H.320/H.323 Recommendations . 30
7.2.6 Evolving T.120 Recommendations. 30
7.2.7 Loosely defined specifications for an MCU. 30
7.2.8 Evolving/undefined specifications for Gateways and Gatekeepers . 30

7.2.9 Loosely defined bandwidth management. 31
7.2.10 Poor standardization of media conferencing . 31
7.3 Product-related Sources of Interoperability Issues . 31
7.3.1 Time delay between the standards (ever-evolving) and products . 31
7.3.2 Implementation of a different subset of the standards. 32
7.3.3 Proprietary solutions. 32
7.4 Implementation-related sources of interoperability issues. 32
7.4.1 Undefined specifications for Gatekeeper Communication. 32
7.4.2 Gateway to Gatekeeper Communication. 32
7.4.3 A decentralized multipoint conference . 33
8 Interoperability requirements. 33
8.1 General . 33
8.2 Call Setup. 34
8.3 Acquisition, processing, and transmission of multimedia data . 35
8.4 Controlling near- and far-end devices .36
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ISO TR 16056-2:2004(E)
8.5 Call termination. 36
9 Interoperability in heterogeneous telehealth networks . 36
9.1 General . 36
9.2 Interoperability of H.320 systems over frame relay network. 36
9.3 Interoperability of h.3xx-compliant systems over heterogeneous networks. 37
9.3.1 Gatekeeper functions. 38
9.3.2 MCU functions. 39
9.3.3 Design requirements – Telehealth solutions . 40
10 Framework for interoperable architectures. 41
10.1 General . 41
10.2 Telehealth component boundaries.41
10.2.1 User interface . 41
10.2.2 Medical Devices . 42
10.2.3 Data manager . 42
10.2.4 Processing Manager . 42
10.2.5 Communications Manager . 43
10.2.6 Resource Manager . 43
10.2.7 Integration Manager. 43
Bibliography. 45

List of Figures
Figure 1 - The H.320 Terminal . 16
Figure 2 - A multipoint configuration. 17
Figure 3 - The H.321 Terminal . 18
Figure 4 - The H.323 Terminal . 20
Figure 5 - The H.324 Terminal . 22
Figure 6 - The T.120 Recommendations. 23
Figure 7 - Parties contributing to telehealth interoperability. 28
Figure 8 - Interoperability dimensions for real-time telehealth services . 34
Figure 9 - H.320 video services incorporated into existing data and voice networks over frame relay . 37
Figure 10 - Connectivity in a heterogeneous system and network environment. 38

List of Tables
Table 1 - Summary of the multimedia conferencing standards. 15
Table 2 - Summary of the H.320 Recommendations. 17
Table 3 - The H.323 and T.120 protocol stack . 20
Table 4 - Summary of the H.323 Recommendations. 21
Table 5 - Summary of functionality of a telelearning system . 25
Table 6 - Summary of functionality of a teleconsultation system . 26

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ISO TR 16056-2:2004(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a 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), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides 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 shall not be held responsible for identifying any or all such patent rights.
ISO/TR 16056-2 was prepared by Technical Committee ISO/TC 215, Health informatics.
ISO/TR 16056 consists of the following parts, under the general title Health informatics — Interoperability of
telehealth systems and networks:
 Part 1: Introduction and definitions
 Part 2: Real-time systems

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ISO TR 16056-2:2004(E)
Introduction
Delivery of health care services by means of telehealth is advancing rapidly. Telehealth enables providing these
services with the use of information and telecommunications technologies. This includes a broad spectrum of
capabilities including acquisition, storage, presentation, and management of patient information (represented in
different digital forms such as video, audio, or data), and communication of this information between care facilities
with the use of communications links.
Telehealth interactions may be carried out in three ways: real-time, store-and-forward or with the use media
streaming methods. While real-time interactions imply that all parties directly participate in the telehealth session,
store-and-forward interactions involve sending, reviewing, and returning an opinion over a period of time.
Streaming is a method of delivery real-time or stored data such as audio, video, documents, still images, or other
data type across networks with a reasonable amount of Quality of Services (QoS). With streaming, a receiving
system can start displaying (or playing) the data before the entire content arrives.
Real-time telehealth sessions usually involve synchronous data transmission while store-and-forward can usually
be regarded as asynchronous. Streaming uses time-synchronized streams of continuous media during
transmission. However, data presentation uses buffering, if the receiving system receives data more quickly than
required. If the data is not received quickly enough, the presentation of the data is interrupted.
Interoperability of telehealth systems and networks is critical in ensuring the telehealth technology serves well the
care recipients and providers and meets their expectations. While this requirement is essential to the long-term
sustainability of telehealth, interoperability is difficult to achieve. There are many reasons that make telehealth
interoperability difficult, however, the following three need urgent addressing: (1) too broad definition of telehealth,
(2) lack of standards specifically designed for telehealth, and (3) collaboration between the information technology
and telecommunications industries.
There are multiple definitions of telehealth. The services provided by telehealth cover a broad spectrum of
activities ranging from videoconferencing through exchange of health information to providing care services in
emergency and complex clinical cases. From a technology perspective, the scope of these services is too broad
and this makes it difficult to develop telehealth standards and products.
There is no ‘official’ telehealth standard. The telehealth industry uses high-level health care guidelines and
technical standards developed for various technology sectors including multimedia conferencing, information
technology, data communications, and security. These guidelines and standards focus on functional and
operational requirements and do not address interoperability. To further complicate the problem, all of these
standards as well as the telehealth needs and practices are rapidly changing.
Telehealth, more than any other recent development, bridges the boundaries between telecommunications and
information technologies. The business goals and attitudes of these two industries are different.
Telecommunications industry has a history of regulation, standardization, and control of the customer premises
equipment. Interoperability and reliability have been the key factors to growth. The information technology industry
(the desktop computing industry in particular) has achieved success through encouraging innovation, diversity,
and tremendous cost-efficiency not always paying attention to interoperability aspects of the technology. The
marriage of these two cultures and the integration of their respective technologies proved to be challenging.
To address the needs for interoperable telehealth systems and networks, telehealth services must be clearly
defined in terms of their scope and interrelationships with other health-related services, a set of telehealth-specific
standards must be developed, and subsequently implemented by the respective industries.
This two-part ISO Technical Report addresses interoperability issues in telehealth systems and networks. This
document has been structured as follows:
Part 1: Introduction and definitions. Covers an introduction to telehealth and includes the definitions of
telehealth, interoperability, and related terms.
Part 2: Real-time systems. Defines the scope of the technical standards related to real-time applications,
(including video, audio, and data conferencing), identifies gaps and overlaps in the standards, defines
requirements for interoperable telehealth systems and networks, and identifies building blocks for
interoperable telehealth solutions.
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ISO TR 16056-2:2004(E)

This Technical Report is to be complemented by two other documents that will cover interoperability of store-and-
forward and media streaming telehealth applications.
The target users of these documents are care providers and health care organizations, telehealth equipment
vendors and implementers of telehealth solutions, professional organizations, and governments.



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ISO TR 16056-2:2004(E)
Health informatics — Interoperability of telehealth systems and
networks — Part 2: Real-time systems
1 SCOPE
This Technical Report entitled Interoperability of telehealth systems and networks – Part 2: Real-time systems
builds on the introduction to telehealth described in ISO/IEC TR 16056-1 Health informatics - Interoperability of
telehealth systems and networks - Part 1: Introduction and definitions and focuses on the technical standards
related to real-time applications, (including video, audio, and data conferencing) and interoperability aspects of
telehealth systems and networks.
Specifically, this document addresses four main areas:
i) Standards for real-time telehealth systems. This Technical Report describes the technical standards
related to real-time telehealth applications, including audio, video, and data conferencing capabilities. It also
identifies gaps, overlaps and inconsistencies in the standards, and provides some guidance about how they
need to evolve.
ii) Interoperability issues in telehealth applications. This Technical Report examines interoperability aspects
of real-time multimedia conferencing standards and telehealth products, and identifies areas of concerns from
the interoperability perspective that need to be resolved.
iii) Requirements for interoperable telehealth systems and networks. This Technical Report defines
interoperability requirements at different levels of interaction between telehealth systems and provides some
guidelines on how interoperability can be achieved.
iv) Framework for interoperable architectures. This Technical Report identifies interoperable building blocks
for telehealth solutions and interactions between these building blocks, and explores the possibility of
standardization of these building blocks.
The scope of the Technical Report does not include conformity and interoperability tests or functional specifications
for telehealth systems and networks.
2 NORMATIVE REFERENCES
This Technical Report incorporates by dated or undated reference, provisions from other publications. These
normative references are cited in the appropriate places in the text, and the publications are listed hereafter.
For dated references, subsequent amendments and revisions of any of these publications apply to this ISO
Technical Report only when incorporated in it by amendment and revision. For undated references, the latest
edition of the referenced document (including any amendments) applies.
CEN/TC 251/N99-097       Health Informatics - Interoperability of Healthcare Multimedia Report
(1999) Systems. Final draft CEN Report
ISO/IEC 17000:2004 Conformity assessment – Vocabulary and general principles
ITU-T Recommendation G.711
Pulse code modulation (PCM) of voice frequencies.
(1988)
ITU-T Recommendation G.722
7 KHz audio - coding within 64 kbit/s.
(1993)
ITU-T Recommendation G.728 Coding of speech at 16 kbit/s using low-delay code excited linear
(1992) prediction.
ITU-T Recommendation H.221
Frame structure for a 64 to 1920 kbit/s channel in audiovisual teleservices.
(1993)
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ISO TR 16056-2:2004(E)
ITU-T Recommendation H.230
Frame-synchronous control and indication signals for audiovisual systems.
(1997)
ITU-T Recommendation H.242 System for establishing communication between audiovisual terminals using
(1996) digital channels up to 2 Mbit/s.
ITU-T Recommendation H.243  Procedures for establishing communication between three or more
(1997) audiovisual terminals using digital channels up to 1920 kbit/s.
ITU-T Recommendation H.224  A real time control protocol for simplex applications using the H.221
(1994) LSD/HSD/HLP channels.
ITU-T Recommendation H.281  A far end camera control protocol for videoconferences using H.224.
(1994)
ITU-T Recommendation H.233  Confidentiality System for Audiovisual Services.
(1996)
ITU-T Recommendation H.234  Encryption key management and authentication system for audiovisual services.
(1996)
ITU-T Recommendation H.320 Narrow-band visual telephone systems and terminal equipment.
(1996)
ITU-T Recommendation T.120
Data protocols for multimedia conferencing.
(1996)
ITU-T Recommendation T.121
Generic application template.
(1996)
ITU-T Recommendation T.122 Multipoint communication service for audiographics and audiovisual
(1993) conferencing service definition.
ITU-T Recommendation T.123 Protocol stacks for audiographic and audiovisual teleconference
(1994) applications.
ITU-T Recommendation T.124
Generic conference control.
(1995)
ITU-T Recommendation T.125
Multipoint communication service protocol specification.
(1994)
ITU-T Recommendation T.126
Multipoint still image and annotation protocol.
(1995)
ITU-T Recommendation T.127
Multipoint binary file transfer protocol.
(1995)

3 TERMS AND DEFINITIONS
For the purposes of this Technical Report, the following definitions apply.
3.1
accreditation
third party attestation related to a conformity assessment body conveying formal demonstration of its competence
to carry out specific conformity assessment tasks

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3.2
A-law
variant of the G.711 audio encoding used primarily in North America and Japan
NOTE Related terms include µ-law and G.711
3.3
asynchronous transmission
transmission of individual bytes without time-dependency between the bytes
3.4
audiographics terminal
terminal that has audio and graphics capabilities, but no video capability
3.5
audiovisual terminal
terminal that has audio, video, and graphics capabilities
3.6
basic rate interface
BRI
ISDN service comprising two B (bearer) channels operating at 64 Kbps each and one D (data) channel operating at
16 Kbps
3.7
call
point-to-point multimedia communication between two H.32x endpoints
3.8
call setup
process of establishing a group of communication users and includes the initialization of any shared application and
other resources which the user may require to be available
3.9
call signalling channel
reliable channel used to convey call setup messages following Q.931
3.10
call teardown
process of ending a call and freeing any resources reserved for that call
3.11
centralized multipoint conference
conference call in which all participating terminals communicate in a point-to-point fashion with an MCU
3.12
certification
third-party attestation related to products, processes, systems or persons
NOTE 1 Certification of a management system is sometimes also called registration.
NOTE 2 Certification is applicable to all objects of conformity assessment except for conformity assessment bodies
themselves, to which accreditation is applicable.
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ISO TR 16056-2:2004(E)
3.13
channel service unit
CSU
interface used to connect a terminal or computer to a digital medium in the same way that a modem is used for
connection to an analogue medium
3.14
charge coupled device
CCD
device used in cameras as an optical scanning mechanism.
NOTE It consists of a shift register that stores samples of analog signals. An analog charge is sequentially passed along
the device by the action of stepping voltages and stored in potential wells formed under electrodes. The charge is moved from
one well to another by the stepping voltages.
3.15
COder/DECoder
COmpression/DECompression
CODEC
hardware and/or software used with interactive video systems that converts an analog signal to digital, then
compresses it so that lower bandwidth telecommunications lines can be used
NOTE The signal is decompressed and converted back to analog output by a compatible CODEC at the receiving end. The
compression method (algorithm) may be proprietary or standards -based.
3.16
common intermediate format
CIF
ITU-T standard video picture scanning format where information is s
...