Siemens EWSD¶

Siemens EWSD (Elektronisches Wählsystem Digital) was a family of digital telephone switch (exchange) which was used by more than 300 telephone operators in more than 100 countries world-wide, serving more than 170 million subscriber lines in 1998.

According to Siemens, there were more than 1600 engineers involved in EWSD software development in Munich alone, creating more than 45 million lines of code.