When did the four-prong connector come out?

[deedubya3800]

It doesn't seem hard to find out online that the modern modular connector came out in the mid-1970s as the result of an FCC order to the Bell System, but when did the four-prong plug first appear? Who introduced it and does it have a name?

[Kenny C]

i read some where that they were first used for connecting desk sets that required separate subsets to the subset. the big guys will clarify

[Phonesrfun]

The 4-prong connectors came out in the 1930's when you needed 4 conductors to connect a 202 to a subset.  The color scheme for the line cord to the subset is Red, Green, Yellow, and Black.  When the plug was used, there only needed to be one subset in the house or restaurant, and the phone mount, itself could be moved at will from place to place.  Restaurants used to be able to take calls for their customers and then bring the phone to the table.

When the phones went to being self contained and no more need for a subset, they still used red and green for the line and a ground connection for party line ringing.  Red and green were standardized for tip and ring on the line and yellow was used for ground.  Black just disappeared, although the plug kept that pin in place.

Ma Bell came out with the design, and others standardized on it.  I don't know the numrerical designations for the various colors or shapes (square versus the later round ones), but someone will have that.  Probably Paul-F.  As far as what they are called, I thing a 4-prong plug is pretty well understood.  If it has another name, I don't know of one.

[KeithB]

When I was growing up in the early 1960s, all our phones were hard-wired to the baseboard or a circuit box. 

[jsowers]

The earliest 4-prong plugs I've seen have been on early 1950s phones. That doesn't mean they weren't made earlier, but they're very uncommon on phones made prior to that era, and especially home phones. Anything could have been retrofitted later, though. The Bell System wasn't into marketing much until the 1950s and these plugs and jacks were promoted to help your phone do double duty and be portable, depending on where you needed it. Even an outside jack was an option.

I have several pictures for those who haven't seen the variety of 283B plugs. Not all of these are mine.

The first plug has a black metal housing and it's very unusual. I wonder if today that would be considered a potential shock hazard.

Second is an ivory 283B with "ears" on it. And a fly.

Third is another "earless" 283B in brown. You can see the 283B imprinted on the bottom. I think the earless ones predated the ones with ears, but there are no dates to go by. They seem to be on earlier phones than the ones with ears.

Fourth is the back of the same type plug. These also came in ivory. And the faceplates sometimes came in dark beige, like this one.

Fifth is a 283B in turquoise. You can see the 283B imprinted on the bottom. Later in the 1950s and 60s these came in colors matching the phones. This was not always apparent to the installer and you see all different combinations on phones from that era.

Sixth, after the 283B came the 505A, with the Bell System logo on it.

Growing up, I didn't have a phone on a jack until I moved away from home in 1984.

[deedubya3800]

Many thanx for all the information! I remember my grandmother had told me that they never had the four-prong type either. They went straight from hardwired to modular.

[KeithB]

That makes me wonder: whatever happened to the 283A 

[paul-f]

You can read up on the subject in the BSPs on this page (461-630-xxx).
       http://www.telephonecollectors.org/DocumentLibrary/BSPs/461Division/fancyindex.php

[JorgeAmely]

Jonathan:

What are the odds of snapping a picture and the fly posing for you?

Talking about WE 283B plugs, I have one (283B) with the AE logo stamped on it.

My sister's house in WV was made in early 1950. It still has a few 4 prong jacks around the house.

[Dennis Markham]

Also notice that the earlier pronged plugs have a hex nut at the base of the prong.  One is able to remove the prong from the plastic piece that holds them.  The later ones are round at the base of the prong and seem to be molded, or pressed into the plastic piece.

[LarryInMichigan]

When did the four-prong connector come out?

Mine came out when I pulled on it

[HarrySmith]

Didnt your Mom tell you not to pull on it

[Phonesrfun]

Many thanx for all the information! I remember my grandmother had told me that they never had the four-prong type either. They went straight from hardwired to modular.

The 4-prong plugs were never in wide spread general use, at least not to the extent modular plugs are used today.  More so just before the modular plugs came out.  

The default standard was hard-wired, and if you wanted to pay an extra fee for the convenience of being able to move your phone from place to place in the house, they would send someone out and put a plug on the end of the phone and install a couple of jacks.  The 4-prong plug was mostly used so you could move a phone from room to room.

The RJ-11 jack came out in the 70's, and was intended to make phone hookup a no-brainer.  This no-brainer approach was particularly useful in the wake of deregulation when suddenly anyone could go buy a phone, but not anyone was capable or even wanted to try hard wiring a phone.

[jsowers]

At the link below is what I think is the precursor to the 4-prong plug, on a 1937 302 that Doug posted today in a different thread. It looks like a standard 1/4" phone plug with two or maybe three conductors. Or an operator switchboard plug. Interesting!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360298101972
( dead link 01-23-22 )

Jorge, the fly landed for someone else and not me. I guess my friend, who took the picture, wouldn't hurt a fly. I, on the other hand, have swatted my share. They seem to make a beeline for me and not my phone plugs.

Also, below is what happened to 505A plugs when (I assume) someone stepped on them, hopefully on the side without the prongs. That's how it came to me. I just replaced the plug with a turquoise one I had already. I think I was able to straighten the prongs eventually. Amazing the plastic didn't crack.

[bingster]

At the link below is what I think is the precursor to the 4-prong plug, on a 1937 302 that Doug posted today in a different thread. It looks like a standard 1/4" phone plug with two or maybe three conductors. Or an operator switchboard plug. Interesting!

Ages ago, Mark Stevens, the founder of our little forum, posted an article from a Southwestern Bell magazine that mentioned these 1/4" plugs for use on 202s.  It was accompanied by a photo, but it was too small to see the plug very well.