I just moved in and I was wondering with this is?


It has 6 pins but I have no idea what it is.


I'd say it's a six-conductor eight-pin RJ-type connector, which means it is not Ethernet. It's likely a (multi-line?) phone connection.

  • Oh, these are all around the house. But they aren’t in the basement, just up stairs and downstairs. There is one upstairs that I just found it’s has labels on it. The first port says line 1 and two. The second port is blocked. The 3rd port just says line 3. So it is just a phone line. Thank you very much for answer my question. I was really curious about this. – John moore Jul 29 '20 at 21:25
  • If you care, there are probably enough wires there that you could turn them into an Ethernet connection instead of 3 phone lines, but you'd likely be limited to 100MB/s because of the cable type, possibly less, and it would only work if they were all full cable runs to a single patch location rather than being bridged from one box to the next. – simpleuser Jul 31 '20 at 21:40
  • 1
    If you do want to use these wires for Ethernet, you would also need to change the sockets or make up some custom adapters. Although a standard RJ45-style 8P8C Ethernet connector would fit, those are 8P6C sockets with only pins 2 thru 7 present. 100Mbps Ethernet needs pins 1, 2, 3 and 6; higher speeds need all 8 pins. – JRI Aug 21 '20 at 8:48

Looks like an RJ25 for 3 phone lines. I used to have "business" phones that used these. Some people refer to them as RJ11, because RJ11 (1 pair for phone, sometimes an additional pair for power to the light in the phone), RJ14 (2 pair), and RJ25 (3 pair) all use the same 6 position (6P) connector size. RJ45 and the Networking equivalent are 8P8C. Old Category 5 10Mbps Ethernet and some 100Mbps "Fast" Ethernet can use 2 pairs but use pins 1,2,3,6 avoiding the center pair because back in 1990 you might have the phone and Ethernet on the same 4 pair cable. You can see more details at https://en.wikipedia.org/wiki/Registered_jack#RJ11,_RJ14,_RJ25_wiring and https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair.

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