I wanted to try connecting to the console port on my Ultra 10 from my laptop running Ubuntu. The only problem is that I have no serial connection on my laptop. I do have a cable that's serial on one end and RJ45 on the other. If it's possible to use that cable to connect the 2 machines, what program do I use?

Thanks

You can't plug an ethernet port to a serial one.

There are USB to serial adapter that may help you.

Don't let the RJ45 fool you, if it's serial on the other side, it's probably a serial over Cat n adapter.

Before the rise of ethernet & thin clients, that was a way of connecting terminals to servers. There would be a "host" (forgive unintended pun) of serial ports at the server end. I have helped convert an office which was wired like that to thin clients & a modern server.

That cable you have, as well as the Cat n in that office, may look like ethernet but the wire/pin assignments are different. I think straight through on all 8 wires, but I'm not sure. In any case, the existing Cat 5 was very handy -- we just cut off the existing plugs & put on new ones that were done right for ethernet.