APC Connector is a type of fiber connector that minimizes backreflection due to a 5° to 15° angle-polish applied to end faces. Like illustrated in the following picture. Because of the angle, the reflected light does not stay in the fiber core but instead leaks out into the. APC, UPC, and PC connectors define different shapes of fiber connector end faces. What are the differences between APC, UPC, PC? How to distinguish them? How to choose between them? This post will tell. What do these words mean? What's the difference between these connector types? This post will shed light on these connector types and. A fibre connector serves as a holder to align and secure a fibre for optimal light transmission when connecting to another fibre.