UPC delivers excellent return loss (≥50 dB) suitable for the vast majority of digital data applications. Choose APC when: Your system is sensitive to back reflection—specifically CATV analog video, PON/FTTX deployments, or DWDM wavelength-division multiplexing systems. Beyond the connector type, every fiber pigtail connector end-face is polished to a specific geometry. Choose UPC when: You're. To put it simply, PC, UPC, and APC refer to the polish styles of the ferrules inside the fiber optic connectors, just as the following figure shows. The ferrule is the housing for the exposed end of a fiber, designed to be connected to another fiber, or into a transmitter or receiver. Either of them is physical contact fiber connectors. What are SC/APC, LC/UPC? You may have heard. As usual, the answer is, “It depends.