International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Deutsche Telekom has been operating different communication satellites for several years. The Satellite Control Center (SCC) of Deutsche Telekom is located near Usingen, about 50 km northwest of Frankfurt/Main. The system has been under operation since the launch of the first flight model DFS in June 1989. The entire computer system was based on Digital Equipment Corporation (DEC) VAX type computers. The maintenance costs of these old Complex Instruction Sets Computers (CISC) were increased significantly during the last years. Due to the high operational costs Deutsche Telekom decided to exchange the operational computer system. Present-day information technology world uses more and more powerful Reduced Instruction Set Computers (RISC). These new designs allow operational costs to be reduced appreciably. The VAX type computers will be replaced by DEC Alpha AXP Computers. This paper describes the transition process from CISC to RISC computers in an operational realtime environment.