We consider interaction between data analysis and telecommunications from both sides, examining the contribution of each discipline to the other. The fast changes in telecommunications have some important consequences. First, the importance of statistics in the design of a network is growing, given the evolution of technology towards more digitalization and the resulting changes in dimensioning the network. Second, the technical tools of statistics are deeply modified, and there is concern about how to take this into account-particularly how to take advantage of the new economy of 'value added services' which uses the network as a 'market place'. K E Y WORDS Statistics Telecommunications Data analysis Value added services Glossary ATM CAD/CAM CSM A/ C D DCT DOSES ED1 ESIA ISDN 1 kbit s -' LAN 1 Mbit s -' O D P PABX PCM POTS VLSI WAN asynchronous transfer mode computer assisted designlmanufacturing carrier sense multiple access with collision detection discrete cosine transformation development of statistical expert systems electronic data interchange enqdtes statistiques et intelligence artificielle integrated services digital network 1000 bits per second local area network 1 OOOOOO bits per second open distributed processing private automatic branch exchange pulse code modulation plain old telephone system very large scale integration wide area network * Special lecture delivered at the Fifth International Symposium on Applied Stochastics Models and Data Analysis, organized by CADEPS,