On the Utilization and Observation of the Efficiency Rate of Telephone Traffic.

Usefulness of the observation of the efficiency and rentability rate of telephone traffic is recalled in order to evaluate correctly actual variations in the subscribers' demand and to implement planning which takes into account the influence of the common organs of centralized control systems. Observation of the efficiency rate requires that different types of failures be observed accurately. In particular, the ″real calls sampling″ method is analyzed. It is usual to provide for a number of observing operators (or pieces of equipment) equal to the tenth of the number of observed circuits which may lead to an unduly great underestimate of the rate of failures due to congestion in the network. Therefore, it is generally preferable to observe almost all the calls, if one wants to obtain an accurate estimate of the efficiency rate.