This brief paper is intended to give the reader an overview of international standards emerging from the Study Group XVIII of the International Telegraph and Telephone Consultative Committee (CCITT). Outlined are the range of impairments seen in digital networks, the CCITT’s current position, and some of the overall objectives.

The paper is concise and brief, admirably achieving the objectives set forth by the author. The style and content both readily deliver the information to the reader in a manner that other authors of technical papers might do well to emulate.