Stored program control: Difference between revisions

Revision as of 21:21, 26 October 2017

Revision as of 17:23, 1 November 2017

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SPC technology using analog switching matrices began to be phased out in the 1980s and had disappeared from most modern networks by the late 1990s.

Viable, fully digital switches emerged in the 1970s, with early systems like the French [[Alcatel-Lucent|Alcatel]] E10 and Candian Nortel DMS going live during that decade. Other widely adopted systems hit the market in the early 1980s. These included Ericsson AXE 10, which would become the world's most popular switching platform, the [[Western Electric]] [[5ESS]] used through the US and in many other countries, the German designed Siemens ESWD, the ITT System 12 (later rebranded [[Alcatel (mobile device brand)|Alcatel]] S12) and [[NEC]] NEAX all of which were widely used around the world. The British developed [[System X telephone exchange(telephony)]], and many other successful smaller systems also emerged in the early 1980s.

Some digital switches (notably the 5ESS and very early versions of Ericsson AXE 10) continued to use analog concentrator stages, using SPC like technologies, rather than direct connections to the digital line cards containing the [[CODEC]].

{{AsEarly of|2017}},in the industry21st movedcentury onthe industry began tousing a 5th generation of telephony switching, as [[Time-division Division Multiplexingmultiplexing|TDM]] and specialist hardware based digital circuit switching is being replaced by soft switches[[softswitch]]<nowiki/>es and voice over IP [[VoIP]] technologies.

The principle feature of stored program control is one or multiple digital processing units ([[stored-program computer]]s) that execute a set of computer instructions (''program'') stored in the [[computer memory|memory]] of the system by which telephone connections are established, maintained, and terminated in associated electronic circuitry.