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International Telecommunication Union
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ITU adopts new releases of SDL and MSC Specification and Description Languages

Geneva, 19 November 1999 — The release 2000 of the widely used specification and design languages SDL (Specification and Description Language) and MSC (Message Sequence Charts) have been approved today by Study Group 10 of the ITU Telecommunications Standardization Sector (ITU-T SG10). SDL and MSC are description languages for communicating systems. Commercial tools have supported SDL and MSC as a proven technology and provided the means for validation, verification, and automatic generation of executable applications and test cases. SDL and MSC tools now have 32% of the real-time software development tool market. New tool releases will support the new standards in the second quarter of 2000.

"These new standards reinforce the long-standing ITU tradition of producing a basis for high-quality standards and products", said Houlin Zhao, Director of the ITU Telecommunication Standardization Bureau" "Already, the use of SDL to specify Intelligent Network standards has increased the quality of the standards while significantly reducing the time for their completion", added Amardeo Sarma, Chairman of Study Group 10, noting that SDL and MSC contribute towards an open and competitive marketplace without being tied to specific vendors or proprietary products. The SDL Rapporteur Rick Reed emphasized the benefit to telecommunication companies and their customers. "You may not see SDL, but the mobile phone and the services you have come to rely on are very likely to have been developed using SDL tools", he said.

SDL and MSC have been upgraded to meet the challenges and the needs of users in the next Millennium. Known for providing error-free specifications and implementations, the languages now more than ever will cater to modern dynamic real-time systems. Together these languages form the foundation for formal and attractive industrial specifications of real-time systems of any complexity.

SDL and MSC were originally designed to specify and describe the behaviour of telecommunication systems and protocols. Today they are also widely used by large telecommunication companies throughout their development processes. The use of SDL and MSC has spread to other fields, such as aeronautics, the car industry and medicine.

Users of SDL and MSC can analyze, validate and simulate system behaviour early in the software development process, thereby slashing development cost. The precise and unambiguous agreement between customers and suppliers on requirements based on SDL and MSC significantly contributes towards achieving interoperable systems in a multi-vendor environment. SDL allows product code to be generated from the high-level specifications.

Following their approval today, the new language standards take effect immediately.

For further information, please contact:

Mr Amardeo Sarma
Chairman, ITU-T Study Group 10
Tel.: +49 228 709-16200
Fax: +49 228 709-16007

Mr Rick Reed
Rapporteur, ITU-T Study Group 10 Question 6 on SDL
Tel.: +44 1455 55 96 55
Fax: +44 1455 55 96 58
Mobile: +44 7970 50 96 50

Mr Øystein Haugen
Rapporteur, ITU-T Study Group 10 Question 9 on MSC
Tel. +47 66 84 2346
Fax +47 66 84 1915

For background information on SDL, you may visit the SDL Forum Society Web site at

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