The Communications system reference article from the English Wikipedia on 24-Apr-2004
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Communications system

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In telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment (DTE) usually capable of interconnection and interoperation to form an integrated whole.

The components of a communications system serve a common purpose, are technically compatible, use common procedures, respond to controls, and operate in unison.