Sonderband 2. International Council on Archives. Dritte Europäische Archivkonferenz, Wien 11. bis 15. Mai 1993. Tagungsprotokolle (1996)

4. Session / Séance. Strategies for Links with Historical Research / Stratégies de Communication envers la Recherche historique - Gonzalez, Pedro: Data Bases and Long Distance Communication. A Spanish Éxperience / Bases de données et information a distance. Une expérience des archives espagnoles (english 319 - français 343)

4. Session/Séance: Gonzalez, Data Bases and long distance Communcation

New advances (principally fibre optics) are going to break this barrier, enabling the arrival and extension of the new networks, which are of far superior capacity to present ones. The concept which is used for measuring the capacity and speed of transmission of these networks is that of „band width“, a margin of frequencies handled by a transmission channel, and that of „bauds“ or number of bits per second which that channel is capable of transmitting.

The possibility of offering a wide range of services (voice, images, data) has lead to the appearance of a new concept of network, a kind of Universal Network, which brings together the services which were formerly offered by several networks within one single network and in simplified form. We are talking, then, of having one single access, which would permit a varied range of services, integrating the already existing networks within a single digital network. The advantages for users and operating companies are obvious.

We are talking of the Integrated Services Digital Networks, or Integrated Services Data Network (ISDN), considered to be Universal Networks, capable of offering all the services of a public type within one single network: improved quality telephony, teletext, telefax, teleconferencing, Videotext, high quality television, interactive television, communication between computers, multimedia databases.

The CCITT defines ISDN as „a network which has evolved from the Integrated Digital Network and which facilitates end to end digital connections in order to supply a wide range of services, both of voice and other types, and to which the users gain access through a defined set of standardized interfaces“. The introduction of this new type of network (introduced in France in 1987 and the USA in 1988), in spite of slow progress in achieving the required international standardization, has now taken significant steps forward, mainly in North America, Japan and the European Economic Community.

ISDN is a development of the present Basic Telephone Network, achieved through several different stages:

1. Integrated Digital Network, which consists of converting all the Basic Telephone Network’s transmission media, switching exchanges and signalling systems. At this stage, at the same time as new media such as fibre optics are being introduced, advances are being made towards compatibility between the different networks.

2. Integrated Services Digital Network - narrowband (ISDN-NB), the first stage of the real digital network, which guarantees the continuity of the previous telephone services at the same time as enabling new types of services to be handled (improved quality telephony, facsimile, Videotext, video-telephony, video conferencing). It has two possibilities of band width, one basic one with two 64 Kb/s channels and another which goes up to 1,5 to 2 Mb/s.

3. Integrated Services Data Network - Broad Band (ISDN-BB), which will enable the integration of all types of services at speeds over 2 Mb/s, although its definitive introduction will take some time, since this depends on resolving

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