I found it! Well, at least I found the connector I was thinking of. Have a look: http://www.deltec.de/kupfer-technik.html?file=tl_files/bilder/Katalogseiten/katalog-2014-seite-66.pdf
based on my subsequent searches based on the words in this PDF, I'm fairly certain it is only used in Germany, and I have no idea how widespread its use is.
EDIT: As far as I can tell, the way it's supposed to work is the bottom two squares (red and green) are for ethernet, the upper left square is phone, and the upper right square is video.
EDIT2: I found an English brochure http://www.vemco.pl/upload/LEONI_Kerpen/Katalog/2009/2009_LEONI-Kerpen_HomeNet.pdf
EDIT3: I found a similar (same?) connector called EC7: PDF
EDIT4: It looks like this is the type of patch cable you need: http://db.leoni-kerpen.com/Datacom/lib/MegaLineNet/PREMIUM/ELine_1200_EC7/pk_e.htm