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Strange outlet in old house (built 1956)! Any idea?

A questioner said this: Strange outlet in old house (built 1956) and sent these photos:

r/whatisthisthing - Strange outlet in old house (built 1956)

r/whatisthisthing - Strange outlet in old house (built 1956)

r/whatisthisthing - Strange outlet in old house (built 1956)

Here is what people said about it:

  1. I have worked in construction, real estate, and facility management for a long long time. I have never seen this before. I think it could be for a sound system or an intercom. But I am only throwing out a guess and I really have no idea. Great Post!!!!!
  2. Here is what we have collected so far:
    • it’s a cinch Jones connector
    • it’s likely a DIY project
    • it’s not connected to the intercom or speaker system as far as we can tell. Existing system is a nutone with different wires.
    • could be for a HAM radio?

    Questions I’m getting and answers:

    • this is in the US
    • we don’t know (yet) if the two outlets are connected
    • it does seem to be low voltage
    • we believe the original owner was an executive, but this style outlet is not in the executive office (could have been removed though, although I suspect not as the people who did renovations left stuff because they were lazy and did cheap work)

    Editing to add something else: a few comments mentioned it could have been for a stock ticker. One of the original owners was a member of the Philadelphia stock exchange, so this is possible. However this outlet is in between the dining room and the living room, the other is in the master. I’d probably murder my spouse if they put something like that in but who knows!

  3. Honestly, it could be anything. Whatever one might want to carry low voltage wiring between that room and somewhere else for.
    • Soldering work and the small receptacle added on below indicate this is homemade.
    • Whatever it is, it was intended to be plugged and unplugged, hence the wall-mounted jacks.
    • That bundled wire goes somewhere! If you can find the other end, you might find answers. Have you looked in the basement?
    Intercoms, doorbell/servant chimes, audio, video or radio equipment, a switchboard to operate something elsewhere in the building… etc.
  4. According to stuff I found on the internet, those 300 series connectors are mainly used in RCA broadcast gear and other vintage audio equipment. I think the intent is to be used in a variety of high voltage applications (rated 500v) where they will be connected and disconnected a lot, and can be configured via soldering wires basically any way you want. So there can/will be a lot of different applications for these connectors. It also looks like they clamp shut for a tight connection.
  5. This is the socket config for a Rock-ola model 1754 Stepper in a jukebox to connect to a remote wall box. Like others said they used a Jones socket. This would carry the pulsed “signal” so when you push ‘A-4’ on the wall box it plays record ‘A-4’ in a jukebox in another room. Although there were other wall box models that were compatible like the Seeburg. The 4 hole socket was probably for the the 25V, Signal, common /ground that would also connect to the wall box. I assume that would power the entire wall box. Like 1950’s PoE 🙂
  6. These are commonly referred to as a “Jones Plug”. They were often used for audio, be it a central intercom, ham radio, tube amp setup or whatnot. They’re actually still used in some commercial communications equipment as they provide a reliable, low impedance connection. I actually have a jukebox that uses this same connection to connect to external speakers / amp. A wire tracing tool can be had for relatively cheap today and could help you figure out where the wires go, which might solve your mystery. Good luck and keep us posted!
  7. Is there a box or panel in the basement or attic that has this mult-pair wire pulled to it? It could be an intercom system but I would think you would see all the speaker panels throughout the house.
  8. Given the type of wire and connectors, this is a custom cable between two places in the house for some kind of specialized equipment.

    It is not for a TV. The cables are entirely incorrect for SCART, composite, component, or for antenna signals of any kind. It’s also not for an antenna rotor, because that only requires 8 wires and would have the other end at the roof. Plus they would have run the antenna with it, which they haven’t done here. The only “TV” thing this could have been would be a very custom discrete wired remote control system designed for TVs before remote controls were common, such as is in a hospital room. But then you have to ask why the ends of the cable are in different rooms.

    It is not for a recording audio system. I worked on these for years. They always employ shielded cables, and you can clearly see here that these are unshielded and not even all the wires appear to be used in pairs.

    It is not for a Yaesu 991 ham radio, because it is 27 positions, not 18 like the Yaesu. Also, any kind of remote ham radio connection from that era would have some cables shielded and likely wouldn’t go that far (for example, a remote VFO would need boosters along the way as well as shielded cables).

    These kinds of connectors were used for lots of equipment back in the day, but not often at home at all. Whatever it was, it was probably very custom and certainly uncommon in homes. The sheer number of contacts implies a high level of sophistication. The twisted pairs could have been used for high-level low quality audio (such as a phone or intercom system), but there really is no way to know. Common phone system connectors, even for sophisticated multi-line systems, did not look like this. Intercoms were less standard, but who builds an intercom with 27 wires between only two points? Only two or three wires are needed for a two-point system.

    You’ll likely never know. But this is so interesting that I would be wondering about it the rest of my life if I passed by that panel every day.

  9. I’m an electrician who has encountered an array of very old installed items. Usually the customer wants me to demo if unused. I’ve never seen anything remotely like that before. The screws look like normal 6/32s. I think other commentators are on the trail when going down the antenna route, but that is just a guess based on what I can rule out in my head.
  10. Okay, here’s my interpretation: This is the wiring matrix that would connect to either an old security system or an intercom. Both use phone wires, so it’s hard to tell. The thing that would plug into this would be a panel with a massive set of prongs that is held up entirely by the prongs themselves.
  11. The houses I grew up in had p.a. systyems in the rooms . Most were wore out or broke . But I remember the garage ones working in two of the houses for some odd reason.
  12. I had a house with a closet full of all sorts of weird outlets. The last homeowner was big into amateur radio. All the cables ran up into the attic and to outside of the house to where a large antenna mast used to be.
  13. The gauge on those wires looks too thick to be a DIY audio job.

    I’m guessing that’s a set of pre-NEMA dual duplex electric power connectors like #4 on here that was ostensibly common to the 1950s era.

  14. Could it be for an intercom from an old door buzzer?

    Edit: The operative word is old. If it was likely abandoned for a newer model, the wires might no longer line up as such or may have also been abandoned in lieu of all-new wiring. I still think it’s an old apartment door-bell/buzzer or lock system with or without intercoms. Some of these components could also have been separate from the newer intercom system.

  15. Speaker wiring for multiple speaker boxes like in surround sound.

    My dad is an electrical engineer by education. I saw him put something like this in when I was a kid.

  16. This is a connection I believe for an old style stock market ticker. It did use an ASCII language but it was like very very very slow. You know like those glass domed ticker tape printers. It tied in with the telephone line somehow…
  17. Have you tried if the two outlets are connected?

    Edit: If not then you could short two pins of one (jam a wire in) and measure those two pins (or better all pins) of the other outlet for resistance

  18. It was custom made. The connectors are commonly called “Jones plugs” made bu Cinch-Jones. The twisted pair wiring is very common in older intercom systems. It was common in the 1950s and 1960s for homes to have radio-intercom systems built into the walls. Typically there would be a master station in the kitchen area that had a radio and amplifier and remotes throughout the house that could be used for communication or to listen to the radio from the master.

    This looks like it was custom built to allow a unit to be unplugged. There are likely more than one, or you may find permanent intercom stations elsewhere throughout the house. This was probably fabricated locally by the company that installed the intercom system.

    Typical manufacturers were Nutone and Bogen. Wiring looks more like it would be used with a Bogen system that has multiple master stations and typically no radio.

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