3Com Fast Ethernet 10/100 Dongle (3C-PC-TX-CBL) Part Number: 07-0337-002. Works with 3C574, 3C575 and 3COM 3C574/575 derivatives without XJACK on them. Dual speed, 10/100 cable using an RJ-45 jack and has two LEDs to show which mode you are in. Cable only!