TBR21

TBR21 is a European telecomminications standard published by ETSI, and is the standard to which all telephone equipment (except simple telephones) must adhere to, to be allowed connection to Europe's public switched telephone network. [ [http://ts.nist.gov/Standards/scopes/1004260.htm Nemko USA, Inc ] ]

It is somewhat equivalent to the US part 68 standard.

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