Fiber media converter is a small device with two media-dependent interfaces and a power supply, simply receive data signals from one media, convert and transmit them to another media. It can be installed almost anywhere in a network. The style of connector depends on the selection of media to be converted by the unit. The most common being UTP to multimode or single mode fiber. On the copper side, most media converters have an RJ-45 connector for 10BASE-T, 100BASE-T, 1000BASE-T and 10GBASE-T connectivity. The fiber side usually has a pair of SC/ST connectors or SFP port. Media converters may support network speeds from 10 Mbps to 10 Gbps, thus there are Fast Ethernet media converters, Gigabit Ethernet media converters, and 10-Gigabit Ethernet media converters.
Fiber media converters change the format of an Ethernet-based signal on Cat5 into a format compatible with fiber optic cables. At the other end of the fiber cable run, a second media converter is used to change the data back to its original format. One important difference to note between Cat5 and fiber is that Cat5 cables and RJ45 jacks are bidirectional while fiber is not. Thus, every fiber run in a system must include two fiber cables, one carrying data in each direction. These are typically labeled transmit (or Tx) and receive (or Rx).
Media converters may be simple devices, but they come in a dizzying array of types. Newer media converters are often really just a switch. Smaller compact switches offer various interfaces on both RJ45 and fiber, which gives a great overall platform to convert from.