An Investigation of Telephone-User Habits by Means of Computer Techniques

This paper presents a study of traffic data collected at the telephone exchange (PABX) of The Norwegian Institute of Technology. A recording system primarily designed for accounting purposes [1] collects a set of data for each outgoing call and stores it on digital magnetic tape. Based on these data a statistical study is carried out emphasizing the properties of traffic sources, single subscriber sources, as well as groups of subscribers. After a survey of the system and the general traffic situation, studies of the call-generation process follow. Called number repertoires are treated, using the concept of entropy. The major part of the paper is devoted to the study of repeated calls. Comparisons are made with results from France and the U.S.A. An important scope of the paper is to point out the potentials of the applied method, implying the high efficiency of data collection as well as processing by means of computer techniques.