The digital data exchange—A space-division switching system
E. Hopner, Michael A. Patten · IBM Journal of Research and Development · 1984
The user requirements for an automated switch for computer terminals in a large establishment or laboratory environment are discussed. This is followed by an explanation of the design requirements, and finally by a description of the significant features of the digital data exchange (DDEX), a microprocessor-controlled user-transparent space-division digital data switch of modular design which is capable of connecting 512 to 2048 lines from various types of IBM terminals to different control units, thereby substantially saving interconnection resources.