HERE ARE SOME OF THE ANSWERS:

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. Found the connector, Beau Cinch P327CCT Jones 27 Pin
3. WITT – I have two of these outlets in my house built in 1956. It was a custom built house and would have been top of the line back in the day. We are thinking maybe an old stereo system but not sure – this outlet is in the dining room and the other is in the master bedroom.
4. Update: it does not match the wires in the intercom or the speaker system. Starting to think a television?
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. Just thinking that could be a distributed speaker system. Sounds similar to an intercom someone else suggested.
7. 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!
8. 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.
9. I think it’s a type of Scart lead socket for taking AV televison signal from one room to another
10. One posting said it fits yeasu 901. It seems to be a ham radio
11. Looks like an old PBX system connection. If there was a home office then they could transfer personal calls and business calls or they had multiple offices. I remember seeing something similar in an old university building.
12. 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.

13. That is so many conductors for 1956. I can’t see it being stereo unless this breaks 2 pair out to a bunch of different rooms. It’s not like there was 7.1 surround back then, stereo LP only came out in the mid 50s.Same for an intercom or phone, unless this is the hub for a lot of rooms there is no need for that many wires.
14. I wonder if it’s the control for an old security system. Makes sense to have a control panel in the bedroom, maybe with a light for each sensor, and then the wires are headed to those sensors (top two rows) and the arm disarm is the bottom connector?
15. a house i did renovation work on used this plug with a intercom system
16. Have you tried plugging in a graphics card? Maybe you can enable RTX for your house then.But seriously I would guess it’s something for an audio PA system. It should be designed for medium electric power(?) and to be very durable, for regular plugging and unplugging…
17. 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
18. 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.
19. 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
20. If this was a hospital I would swear it could be a multi-pin connector for an old bed/nurse call system. Although those were almost always round connectors.

WHAT DO YOU THINK? LET US KNOW IN THE COMMENT!

READ ALSO : The whole internet collaborated and couldn’t find what this is. I’m not sure what this is, ninety percent of people don’t know too…

Source: lilacjive