Below, we explore key issues that may arise during the production of fiber optic patch cords, including end-face quality, high insertion loss, diameter discrepancies, appearance defects, assembly issues, and failure to meet customer requirements. Unlike backbone cables, patch cords are frequently connected, disconnected, bent, and handled by technicians, making them the most vulnerable. While this was only a minor issue, it greatly affected both the optical alignment and, as indicated by test results in the field, return loss, which ideally should be approximately -65 dB, increased to 20 dB or more because of light reflecting into transceiver modules. The result of feedback at the. Consequently, understanding how Patch Cord issues emerge is essential for maintaining a resilient optical infrastructure. How Patch Cord Contamination Leads to Direct Physical Signal Loss Contamination remains the most common and destructive threat to Patch Cord performance. At Gcabling, our advanced manufacturing and strict quality control processes ensure. These problems may be caused by software delay, server abnormal, Priority setting, fibre broken. Here we are discussing another two factors: Insert Loss, end face of connector. End face normally may has problems as below: 1.