The reaction of subscribers on the failure of call attempts

In this paper the preliminary results of a measurement are given which treats the reaction of subscribers in a p.a.b.x. on the failure of call attempts. Reasons for the failure of call attempts are line busy, subscriber busy, subscriber errors, no answer of the called subscriber, and defects of the telephone system. This measurement of subscriber behaviour has to answer three questions: (1) which is the reason of the failure, (2) does the subscriber repeat the call attempt, (3) how long is the interval between the unsuccessful attempt and the next repeat.