RJ11 is for phone, RJ45 is ethernet. Connecting the telephone system to an Ethernet jack can supposedly break the phone system or short it out or something. Y

RJ11 is for phone, RJ45 is ethernet. Connecting the telephone system to an Ethernet jack can supposedly break the phone system or short it out or something. You can often plug RJ11 into an RJ45 jack, it will fit and make some contacts, which is often done to save on in-wall wiring costs in mixed networking deployments where you're still using POTS and not VOIP. http://en.wikipedia.org/wiki/RJ11,_RJ14,_RJ25 http://en.wikipedia.org/wiki/RJ11,_RJ14,_RJ25 http://en.wikipedia.org/wiki/8P8C http://en.wikipedia.org/wiki/8P8C