"In the past, if you wanted to run Ethernet from your workstations and hubs, you had to consider the expense of converting your entire building's Type 1 cable plant to utp cabling. Now you can leave your cable plant in place and simply use these baluns to convert from the Token Ring data connector at the wall plate to RJ45 utp cabling. Simply plug the balun's data connector end into the Type 1 wall plate jack and plug in your 100 Base-TX Ethernet device (NIC, hub, etc.) into the RJ45 end of the balun with a standard Category 5 patch cable. The balun matches impedances of a 100 Ohm RJ45 terminated cable and a 150 Ohm Sto cable (cable plant), and achieves frequencies up to 100Mhz. Allows for connection of a 100Base-TX hub or adapter card with RJ-45 ports to an existing IBM cabling System. Matches impedances of a 100 Ohm RJ-45 terminated cable and a 150 Ohm Sto cable for frequencies of up to 100Mhz. High Performance: 0.5dB insertion loss from 0.1 to 100Mhz, less than -32dB crosstalk at 100Mhz."