Subdivision of telephone traffic

Traffic data for engineering of telephone switching equipment is usually derived from traffic measurements extended over as large a number of circuit groups and as long periods of observation as practical. The quantities of equipment required in circuit subgroups are then based on the average traffic, prorated to the particular subgroup. The factors governing this averaging process will be analyzed under case I. The converse process, where the total traffic is estimated from observation on a few sample subgroups, is less often used in engineering equipment quantities. In latter instance, Case II, standard methods of statistical estimation are applicable, with additional adjustments which correspond to those discussed herein.