In No. 2 ESS modem telephone features are provided by concise call processing programs, which make extensive use of subroutines. This paper discusses the features to be available with the introduction of the system. It describes the call processing program plan used to achieve efficient use of program storage and gives details of supervision processing, digit handling, peripheral equipment control and translation. This paper also describes how call processing programs control the progress of an intraoffice call, and how they are used in testing of trunk and service circuits.

No abstract