Type-on carrier telephone

IN THE normal process of laying out toll circuits, it is found that many of the circuits will be made up of a combination of open wire and cable facilities. The new short-haul carrier systems will be found on many of the facilities, type-O on open wire1 and type-N on cable.2 Consequently, in built-up circuits, it will frequently be necessary to interconnect O and N carrier facilities at the open wire cable junction. The junctions of open wire and cable will occur most frequently at population centers which serve as terminals for the two facilities. However, there will be numerous cases where the junction will occur at the frontier of the cable expansion program, and may represent a complete change of facility from open wire to cable in the center of a route.