Optical Transmission for Interoffice Trunks

There is general agreement among members of the engineering community that the interoffice telephone trunk is a prime candidate for commercial application of fiber optical systems. Field performance, in terms of endurance in a working telephone environment, remains as one of the few questions to be answered. A fiber optic transmission system was installed between two telephone central offices to demonstrate the performance of a practical system. The installed system uses Burrus Type LED sources and APD detectors. Most of the ancillary equipment uses conventional electronics. This paper describes the operation, considers the similarities between optical and metallic transmission requirements and discusses the method of route selection. The installation of fiber optic cable in existing underground ducts will be covered as well. Hand tools for fiber splicing developed specifically for field applications, will be described and their use will be discussed. Features characteristic to optical transmission will be accentuated.