This video will show you how to repair a damaged fiber optic cable strand without a fusion splicer. This temporary fix will get your network back up and running, giving you time to source new fiber cable. While fiber optic cables are generally more reliable than traditional copper cables, they can still experience problems from time to time. However, when I plug Single mode fibre in Multimode module both side of switch link come up. Any reasons why it is happening. Why multimode fibre is not working with Multimode SFP Module? Someone suggested because MM. Fiber optic troubleshooting is an essential skill for network administrators, technicians, and engineers responsible for maintaining and repairing fiber optic systems.