Any old cable should work, with the proviso that some old 10 megabit Ethernet transceivers don't get along with faster auto-sense ports, and if you really get old some don't like full-duplex. (meaning they work okay with hubs, but have issues with switches or crossovers that assume full.) Try it, and if it doesn't work that is probably the problem. (the easy workaround is to use an old hub as a go-between.)