Insertion loss deviation (ILD) caused by component impedance mismatch in a copper channel is a consideration at higher frequencies in high-speed, full duplex applications as it can create noise that degrades performance. To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. The estimate, called a "loss budget" is calculated using typical component losses for. Insertion loss is the amount of energy that a signal loses as it travels along a cable link. It is a natural phenomenon that occurs for any type of transmission—whether it's electricity or data. The uses various types of network cables, including multimode and single-mode fiber-optic cable. While a small percentage, we can examine the “intrinsic” cable failures and what is done to prevent. This paper attempts to provide an answer to the question: To what accuracy can insertion-loss measurements be made on low-loss, multi-mode fiber-optic cables, patch cords, and modules having a variety of terminations? To answer this question, and to provide insight regarding the factors that.