AT&T CCITT Signaling System Number 7 for International Service

This paper discusses AT&T plans to introduce CCITT System No. 7 for international service. Since System No. 7 has a number of national options in the Message Transfer Part (MTP) and user parts, it will be necessary to provide compatible interfaces at International Switching Centers that can efficiently work into national switches and call processing routines. The paper outlines the basic approach taken by AT&T to provide an international MTP and Telephone User Part (TUP) interface for international service that can be used to provide basic call set-up from its International Switching Centers.