Serial communication has distance limitations. Breakages in multidrop connections lead to loss in data making it unsuitable for critical communication. The SC12FS SH I is a Self-Healing RS232/RS485/422 to Dual - Full Duplex Fiber port converter forming a Redundant Optical Fiber ring. Instead of multidropping Serial devices on RS485, you can effectively multidrop them on Fiber, giving you the advantage of Redundancy, distances as large as 100 km instead of 1.2Km, as well offering immunity to various types of noise and increase the dependability of data. A communication failure is sensed, if any of the Slave node fails or the Power goes off or there is a break in fiber etc. If the primary path breaks, the communication continues unhindered from the Redundant path. The communications model is one Master and multiple Slaves. It is easy to structure a network of Star, Daisy Chain or Loop type. You need at least 3 converters to form a ring.