The Cisco Catalyst 4000/4500 Series 24-port 100BASE-FX MT-RJ line card provides 24 Fast Ethernet ports over multi-mode fiber for runs up to 2 km. Fast Ethernet over fiber is well-suited for high security environments as fiber is a more secure medium than copper. It is also good for industrial environments as noisy electrical areas do not interfere with optical transimissions and remote locations where networking equipment is located more than 500 m from the aggregation point.