This media and rate converter line card features a 10/100TX twisted pair port and a 100FX optical port. The twisted pair has an RJ-45 connector and a maximum operating distance of 100 meters (328 feet) when connected to an Ethernet or Fast Ethernet device. They operate in full or half-duplex mode, and allow you to build an affordable network, avoiding the cost of terminatiang fiber cables. The AT-CM301 has a multi mode fiber ST connector and operates up to 2km.