Call Waiting - History

History

Call waiting was introduced to North America in the early 1970s when the first generation of electronic switch machines built by Western Electric, Electronic Signaling System 1 started to replace older mechanical equipment in the old Bell System local telephone companies. At first, some smaller municipalities had it only on a specific phone exchange (e.g., phone customers in Trenton, Michigan initially had to have a phone number starting with 671 to have call waiting, since 671 was at that time the only exchange in that area served by one of the new ESS switches), but as demand for it became more widespread, it eventually became available on all phone exchanges as the older equipment was phased out.

In Europe call waiting was also introduced in the 1970s with the introduction of the first digital switching systems such as the Ericsson AXE, Alcatel E10 and System 12. It was also available on some Ericsson crossbar exchanges, such as the ARE11 which, while electromechanical, was computerised. Other digital systems such as the UK's System X also supported the service. Switching systems developed in the 1980s such as the German Siemens/Bosch EWSD also had call waiting.