Fiber optics are becoming an increasingly popular means of transmitting data in industrial environment. The combination of high speed over long distance and being totally immune to electromagnetic interference makes this medium ideal. Westermo provide a number of devices and configuration options for fiber optics, these include ring and bus, point to point and multi drop networks on RS-232/422/485. The ring configuration is generally used where a high tolerance to fault conditions is required, such as safety critical systems on oil rigs or chemical plants. On a ring system a failure on a set of fibers will not result in a loss of communications unless 2 or more sets of fibers have been broken. Multidrop fiber networks like the one shown below can be used as an alternative to traditional copper based networks such as RS-485/422 networks.