Telephone exchange equipment

open source software implementing a private branch exchange for various Voice over IP protocols

multiline telephone system typically used in business environments

electromechanical line selector for automatic telephone exchanges

switch used in analogue telephone exchanges

thumb|right|Block diagram of the EWSD digital switching system The Elektronisches Wählsystem Digital (EWSD), translated to Electronic Digital Switching System in English, is a widely installed German telephone exchange system, originally introduced in 1975 by Siemens AG, but discontinued in 2017.