The Chicago Long Distance Toll Board

The long distance telephone office serves to provide a concentration point for intercity telephone communication from a group of local exchanges and its size will depend largely upon the number of stations served by the local offices. The Chicago Toll office, which serves 1,200,000 stations, has recently been largely replaced with new equipment. This equipment, together with correlated improvements in handling toll service at Chicago, is described in this paper. The work of the toll operator in handling toll calls with the new equipment is compared with the former method and it is this change in operating practise which constitutes a major improvement in long distance service. The paper also includes a description of the toll lines entering Chicago with their equipment arrangements including telephone repeaters and the power plants required to operate this equipment and that associated with the switchboards. The addendum describes the purpose of the auxiliary and special switchboards which are required only in large installations such as Chicago.