Standards such as IEC 61300-3-47, Basic test and measurement procedures for end face geometry of PC/APC spherically polished ferrules using interferometry, and a series of IEC 61755 standards covering angle polishing, ferrule geometry, materials, and other connector parts . Standards such as IEC 61300-3-47, Basic test and measurement procedures for end face geometry of PC/APC spherically polished ferrules using interferometry, and a series of IEC 61755 standards covering angle polishing, ferrule geometry, materials, and other connector parts . out a few important aspects. To begin with, Insertion Loss (IL) and Re-turn Loss (RL) are crucial parameters which determine the quali y and the ferrule's class. No to mention that it is the ferrule, which is the core component o each fiber optic connector. An optical fiber is placed in its. Understanding fiber connector types—SC/APC, SC/PC, LC/UPC, LC/APC, ST/PC, FC/PC, and FC/APC—is essential for selecting the right interface for your application. The glass strands in the fiber optic cables are known as optical strands. What are the differences between APC, UPC, PC? How to distinguish them? How to choose between them? This post will tell.