I am trying to identify a mystery wall receptacle that I have in my house (built in the 60s, USA). I have one in the living room next to a fireplace, another in a bedroom. It looks somewhat like the C8 socket, but is more rectangular and rough-looking.

Does anybody know what this is?

EDIT: added opened picture

Mystery wall connector

Opened plate

  • an early phone socket? or for a speaker?
    – Solar Mike
    May 12, 2019 at 18:30
  • 3
    A duplicate of this question, I believe: diy.stackexchange.com/questions/29430/…
    – jwh20
    May 12, 2019 at 18:48
  • 3
    As the flat wire is now exposed it is a tv antennae connection and this is a duplicate of the other question
    – Kris
    May 12, 2019 at 18:52
  • 2
    Thanks everyone, I think this is indeed the same socket as the other question.
    – Daniel S.
    May 12, 2019 at 18:54

1 Answer 1


Thanks for providing the "opened" picture, which clearly reveals that this is 300 ohm TV (and/or FM radio) antenna twinlead.

Not quite as obsolete as a buggywhip, but pretty close.

  • +1 for "twinlead". That was indeed the type of antenna lead wires.
    – Michael Karas
    May 12, 2019 at 20:22
  • Are HD antennas not roof mounted, and signal over this wire? May 13, 2019 at 1:57
  • 2
    The original TV antennas this stuff was common for still work with HDTV if you have them (you don't actually need a "HDTV Antenna"), but most modern antennas use a 75 ohm coaxial feed rather than twinlead. It's shielded by design, which reduces interference pickup. It's also a LOT easier to find hardware for, these days.
    – Ecnerwal
    May 13, 2019 at 2:07

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