So, to cut right to the chase, you can generally tell if fiber is multimode or singlemode by examining the cable's jacket color, looking for printed markings on the jacket, checking the connector type, and if all else fails, by measuring the core diameter or using an optical. So, to cut right to the chase, you can generally tell if fiber is multimode or singlemode by examining the cable's jacket color, looking for printed markings on the jacket, checking the connector type, and if all else fails, by measuring the core diameter or using an optical. Knowing how to tell the difference between single mode and multimode fiber is crucial for network efficiency; the core distinction lies in the fiber's core diameter and how light travels through it, affecting bandwidth, distance, and cost. Fiber optic cables transmit data as pulses of light through. ISO/IEC 11801 defines the OM1, OM2, OM3, OM4, and OM5 types of multimode fiber. It also lists the key technical requirements for each type. These differences include the maximum distance and speed. This Applications Engineering Note (AE Note) discusses the criteria for properly selecting the optimal multimode fiber (MMF) for enterprise applications. This AE Note classifies multimode fiber according to the following broad categories. Customer requires to calculate approximate bandwidth of the system in 3 differing networks.