To analize the minimum requirements in a Telemedicine service or device we should know:

  1. Type of information to be send: Audio, Data, Fax, Still Images, Motion Video
  2. Type of communications & networking: Networking architecture, POTS, ISDN, ATM, GSM, Satellite
  3. Displays: Analog, digital, laser.
  4. Human and Organizational factors ( see Chapter 7 )
  5. Legal aspects ( see Chapter 8 & 9 )

An in those which already available which are the European or international standards , rules and legislation. Also a basic knowledge of the Standardization committees is required.( in Annex I )

1.- Type of Information to be sent


1.2 DATA

1.3 FAX


  1. Low resolution
  2. High resolution:

Still image standards:

Other image formats :

One IOD ( Information Object definition ) allow the representation of entities ( class of real world objects that share the same properties ) Each attribute is a different propriety of the entity.
A SOP class ( Service -object pair ) is the union of an IOD with the applicable service group.
A Service Class specification define a group of one or more SOP classes related with a specific function ( for exaple functions related with a remote storage ( Storage Service Class ) or with an object search ( Query/retrieve service class )

1.5 CSCW ( Computer supported cooperative work ) which is a distributed application that can be concurrently used by a group of interactive users. Is an intermediate situation between data and image transmision. Require:

  1. Representation of data objects and relation between them
    • DICOM
    • SGML
      • - HTML
      • - HyTime
  2. Presentation of data of the users and synchronization between them
    • MHEG ( Multimedia &Hypermedia Information object expert group )
    • WYSIWIS ( What You See Is What it IS )



2.- Types of communications and networking

2.1 NetwoRking architecture : The ISO model is the basic reference model to assure a total interconnection between systems. This does not mean that the systems will be really compatible but at least that they contain specifications that allow compatibility with appropiate interfaces.

The 7 levels of the ISO model include :

Level 1 Physical Layer : RS-232,RS-449, V37,V17,V28, DICOM 20 pin connector etc...

Level 2 Data Link Layer : rules for transmission and reception through the physical layer

HDLC( data link central ) ; LAN controles and access methodos to Ethernet ( IEEE802.3 ), Troken Bus ( 802.4 ), Token ring ( 802. 5), Fast Ethernet, ATM and Frame relay; Interface for lan controles such as NDIS ( network Drivers Interface specification )

Level 3 Network level. Protocols that assure the opening and mantainance of connection in the network

IP ( Internet Protocol ); X.25 ; IPX ( Internetwork packet exchange ),VIP ( Vines Internet protocol)

Level 4 Transpor Level .High control level to transport information between systems including sofisticated utilities for error control, priority, security etc..

TCP ( Transmission control protocol ), UDP ( User datagram protocol ), SPX ( sequential packet exchange ), VICP-VINES, NetBios/NetBeui

Level 5 Sesion Level .Dialog between systems to know what the other are doing H231, Apple-Talk

Level 6 Presentation L. The norms used to define the applications that produce transfer files,message .. TELNET, Unix virtual terminal ; fTAM file transfer accesionel management; DTP ,distributed transaction process, X.400 management mesages, EDIFACT sintax rules,; e-mail : SMTP ( simple mail transport protocol ), POP3 ( post office protocol ), MIME ( multipurpose internet mail extension ), IMAP4 ( internet message access protocol )

Level 7 Application layer

2.2 POTS ( see Chapter 4 ) Public Old transmission system

2.3 ISDN ( see Chapter 4 ) Integrate service digital network

2.4 ATM. Asynchronous transfer mode networks

Most national ATM backbones are connected in a pan-European ATM backbone network
Speed from : 2Mbps to 155 Mbps
Other Fixed networks are : SMDS ( Switched Multimegabit Data Service ) and Frame Relay

2.5 GSM

Support transmission fax/data at 9600 bps. Networking of various channels is possible ( Nokia )
Transmission mode can be:

A GIWU ( Gateway InterWorking Unit ) such as the Ericsson, support compatibility towards PSTN modems : V.21, V.22, V.22bis, V.32 and V.42

2.6 Satellite :

Satellites services, can be divided into

  1. Private VSAT ( Very small antenna Terminals )
    • Structure of the network assure confidentiality ( no access to unauthorised users )
    • Different satellite networks are not compatible, some have user agreements
    • Low cost antenas ( 1,8 diameter)
    • In general point to point; multipoint is also available
  2. Public INMARSAT ( International Maritine Satellites )
    • Are public networks directed by PTTs.
    • Have 4 standards :
      • Standard A.- Analog at 9,6 Kbs. Data up to 64 Kbs
      • Standard B.- Digital at 9,6 Kbs. Data up to 64 Kbs
      • Standard C.- No voice. Data up to 600 Kbs
      • Standard D.- 4,8 Kbs. No voice. Data at 2,4 Kbs

3.- Displays

Quality of displays are mandatory in order to assure :

* User friendly devices

* Diagnostic capabilities

On Image-based Telemedicine services, teleradiology is the only one that have standardized their display devices ( see Chapter 3 ) according to their applications :

a) Small matrix applications 0.5 K x 0.5K x 8 bits devices

b) Large matrix applications 2K x 2K x 8 bits devices.

Noticed that although images could have a wider dinamic range ( 12 bits ) the limit due to signal/noise ratio of displays devices is 10 bits and limit of human eye is 6 bits.

Display devices according the technology can be : Analog, Digital, Laser displays

3.1 Analog

3.2 Digital

3.3 Laser displays.

The latter degenerations of displays ( Scheider technology ) that allow...


4.- Human and organizational factors.

Chapter 7 introduce the outstanding importance of the organizational enviroment, the role of the Studio in the delivery of services and the importance of human impact in an efficient Teleservice.
Succed in Telemedicine applications also include economic analysis but particularly the hability to design mission oriented telemedicine policies ( see Chapter 10 ).
As an example of the mission oriented policies we may include the psychiatry individual support at distance that require:

  1. Special islotation and privacy for patient and psychiatrist.
  2. Distant Videocamara monitoring for emotional control and detection
  3. Smooth notbreaking telecommunication systems that assure an adecuate progressive psicological transfer.


5.- Legal aspects ( see Chapter 8 & 9 )

Topics related with the legal enviroment that may facilitate the development of Telemedicine are:

  1. Legislation to substitute written papers for electronic data ( including overseas health care ) ( final implementation period in EU , October 2007 )
    1. Legal acceptance of electronic patient records
    2. Legal acceptance of digital radiology and electronic laboratory results
    3. Legal acceptance of electronic prescriptions
    4. Legal acceptance of electronic economical transactions in Health care
  2. Legislation to assure privacy and confidentiality in electronic data
  3. Recognition and payment of Teleservices in Medicine
  4. Legal framework for habilitation to provide and use Teleservices in Medicine
    1. Training in Telemedicine services
    2. Safe and security framework for electronic devices and transactions in Telemedicine
    3. Standard promotion : use and integration.


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Revisado: lunes, 26 mayo 1997.
Con el soporte informático y de comunicaciones del CICEI, Universidad de Las Palmas de Gran Canaria