Thanks for sharing this, first time I've seen such device, I'd like to add other options that I experienced and would suggest;

- Open your telephone socket, if the actual cable has 5 pairs, it's probably a cat5e cable. It can do 1gbps with a RJ45 connection, just replace the plug and connect tou your device to check, yo ucan get a cheap ethernet cable tester too. If it has just 3 pairs, it can probably do 100mbs automatically with most ethernet capable devices. - If you just need to connect 2 devices, you may probably just use existing cables to do it. More than 2 devices would not work. - If it doesn't work, all those cables probably go to a box, find it and check if they are connected, if not yo ucan just crimp the ends together.

Other alternatives: - As others mentioned, MoCA devices are also able to deliver 1gbps, and there is a higher chance that you may find them in most rooms, and they are almost always connected, so it shoudl be plug&play. - Powerline adapters novadays not too bad as well. I was able to use them in a 30 eyar old home, 3 floors up to provide 500mbs.