3 (out of the
4. SO= TRANSBORDER DATA FLOW APPLICATIONS
4.1. Transborder Activity of t h e Regional Teleconnmunication Center of t h e Czech Hydrometeorological Institute [ID]
The Regional Telecommunication Center (RTC) of the Czech Hydrometeorological Institute was established in 1972 and is respon- sible for data transmission within the WMO-GTS (World Meteorological Organization) and the ICAO (International Civil Aviation Organization) networks. It provides connection among the others with the World Meteorological Center in Moscow,with regional telecommunication centers in Vienna, Offenbach, and Sofia, and national meteorological centers in Potsdam, Warsaw, and Budapest. Within the ICAO network RTC is connected with centers in Budapest, Berlin, Moscow, Warsaw, and Vienna. For data communication,a wide range of transmission rates are used: 50-200 bit/s for national meteorological purposes, 100 bit/s for ICAO purposes, and 100-2400 bit/s for WMO purposes.
Data a r e exchanged over FDX 4-wire leased telephone lines equipped with modems both in synchronous mode and asynchronous (start- stop) mode.
Subscribers to the telex network have access to the RTC via universal DTF,s. The RTC provides many different services: message switchng for W M O and ICAO, selecting, editing, and correcting of meteorological reports, subscriber dlalogue with an average response time of 1 second, databases of origlnal and selected
messages, code conversion (ITA 2, IA 5 ) , transmission r a t e conver- sion, error control, etc. Most of the RTC hardware is duplicated for higher reliability. The RTC is in operation for 24 hours a day, and daily receives about 10 million characters and transmits 40 million characters.
4.2. Remote Access to SITA [ l l . ]
The Czechoslovak Airlines (CSA) is connected to the SITA (Societe Internationale de Telecommunications Aeronautiques) net- work to the Seat Reservation System GABRIEL run on UNIVAC com- puters, in Atlanta (USA) via the SITA Main Communication Processor in Frankfurt and Satellite Processors both in Zurich and Munich.
Data a r e exchanged over two HDX trunk lines a t a transmission rate of 4800 bit/s and over remote national lines that a r e controlled by the cluster controller in Prague, which assures high reliability and data flow flexibility.
The Czechoslovak domestic sub-ne twork involves more than 60
VDUs
and 15 matrix printers, which are placed in two reservation control centers, two airports, and five town offices. The inquiry sys- tem provides identical services t o SITA's, e.g., storing and updatlng flight timetables, booking, changing or cancelling air tickets, avoid- ing duplications of reservations, reporting statistical data, informing about vacancies and connecting lines. The response time, in spite of the long distance to Atlanta, is very short--on average, approximately 3 seconds.4.3. International Connection for Scientific. Technical, and Economic Information Exchange [I21
Within the Czechoslovak Scientific, Technical, and Economic Information (STEI) system, a Central Technical Base (CTB) was esta- blished, w h c h enables inter-alia the direct access to databases of STEI. For the purposes of information exchange with databases in Eastern and Western European countries, the experimental d a t a con- nection VNIISI (Moscow)-CTB (Prague)-IIASA (Laxenburg-Austria) was established in 1981. The connection is based on a leased 4-wire tele- phone line equipped with modem 4800 bit/s. The data flow is routed a t CTB by means of time division multiplexers.
The CTB provides among others:
--
access to Czechoslovak databases for Soviet organizations,-
STEI exchange between scientific institutes in the CSSR and in the USSR-
access t o Soviet and Eastern European databases for Czechoslovak organizations-
centralized control of the orders of primary records (docu- ments) on the basis of o n - h e Western European database systems.It can be expected that t h e exchange of ST]. (Scientific Technical Information) in the future will grow and new connections will be esta- blished to promote t h s .
5. SUMMARY
As in other countries, the demand for data communication is increasing in Czechoslovakia. However, according to the PTT its demand has not yet required the establishment of a dedicated digital P?T data communication service. Thus data communication services by the PTT are provided through the existing telecommunication networks, through telephone, telex, and telegraph lines, w h c h fully satisfy the present data communication requirements both in speed, quality, and volume. As to the t e c h c a l characteristics of such services the Czechoslovak PTT strictly follows the appropriate recommendations of the CCITT. Similarly the telecommunication equipment industry follows the standards of IS0 and CMEA.
The importance of transborder data flows for Czechoslovakia--a small country with an open economy-is not to be overlooked. The country plays a n important role, for example, in the WMO-GTS network, actively participates in the networking activities of ICAO, and in the exchange of scientific and technological information over computer networks. It can be expected that the scope and volume of this transborder data fow traffic will f u r t h e r increase in the future.
REFERENCES
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[31 Bek,
Z.,
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[ 41 Index of Economic Development in Forelgn Countries (in Czech), 1980. UVTEI Prague.
[ 51 Data Communication Regulations (in preparation). Federal Ministry of Post and Telecommunications.
[GI Puzman, J., 1979. Data Communications in Czechoslovakia (in Russian). Vychislitelnaya Tekhnika Sotsialisticheskikh Stran.
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[ 91 Bulletin of the Federal Ministry of Post and Telecommunica- tions, (in Czech), 179. No. 29/1979.
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