If high interference immunity is needed or long transmission distances are involved, then fiber-optic cables are advisable. Another advantage of using fiber-optic cabling is the insensitivity to lightning or voltage surges. The use of fiber-optic based systems is already established in areas such as the process industry, plant engineering, energy distribution and wind energy. One simple and inexpensive solution is offered by Weidmuller media converter. This connects the Ethernet via an RJ45 port to an optical fiber-optic cable port with SC or ST glass fiber connections. This retains the collision domain between the two Ethernet participants and means that there is status transparency exchanged between the two Ethernet interfaces and the port status. Multimode glass fibers allow distances of up to 5,000 m to be bridged without intermediate repeaters. Singlemode fibers can be used over distances of up to 40 km.