FOSTC Fiber optic cabling has inherent resistance to EMI/RFI and transient immunity, making it ideal for industrial and utility data communication applications. The FOSTC was designed to provide the most versatile connection possible between any asynchronous serial equipment using Fiber Optic cable. The FOSTC can be used for point-to-point communications between serial devices, or in a multi-drop fiber ring configuration, allowing multiple serial devices to communicate with each other. It allows any two pieces of asynchronous serial equipment to communicate full or half-duplex over two fibers at typical distances up to 2.5 miles (4 km). To extend the distance of the fiber link beyond 2.5 miles, use B&B model FOSTDRP Fiber Optic Repeater.