If you have two buildings in Packet Tracer that are "too far apart" for copper, you would use a switch at each end to convert the local copper signal to fiber for the long-distance run.
Ensure both ends of the fiber cable are plugged into Fiber/SFP modules. You cannot plug a fiber cable into an RJ45 port. media converter in cisco packet tracer link
If your media converter link shows a (down status), check the following: If you have two buildings in Packet Tracer
By default, Cisco ports may be "shutdown." Go to the CLI and type no shutdown on the specific interface. If your media converter link shows a (down
Look for modules like the or PT-SWITCH-NM-1FGE (Gigabit Interface Converter).
In the physical world, a is a simple networking device that connects two different media types—most commonly copper twisted-pair (Ethernet) and fiber optic cabling. They are essential when you need to extend a network link beyond the 100-meter limit of standard copper Ethernet or when integrating legacy equipment with modern fiber backbones.