Fiber optic cable is the network cable type least susceptible to signal interference. Because it transmits data as pulses of light through glass threads rather than electrical signals through copper, it is completely immune to electromagnetic interference (EMI). Fiber. They support high-speed, interference-resistant communication and are particularly effective in applications that require high bandwidth, low latency, and strong signal integrity. However, not all fiber cables are built the same—especially when they're deployed in harsh environments like industrial plants, military zones. They do this (by keeping signal losses and interference down to a minimum) with tidy connections. But if installed improperly, they will be exposed to EMI from electrical cables.