Discussion of what was wrong with four-prong plugs, why they were eliminated

[bellsystem]

I know this is going to sound strange but please hear me out:

As far as I know, the 3 major "eras" of telephone handset wiring were as follows:
A) Hardwired. No modular components. Line cord screwed into wall terminal.
B) Four-prong. Line cord has a four-prong plug that plugged into a four-prong jack.
C) Modular (half-modular, quarter-modular, full modular) - Where the now ubiquitous "RJ11" gray line cord was introduced ~1970s

Technically, I consider the 4-prong plug to be "modular" in some way, since it can be easily removed and replaced in the wall jack.

I like phones that have 4-prong plugs the best because the LINE CORD itself is COLORED (and it matches the color of the phone), which you obviously don't get with RJ11 line cords. Furthermore, the tips of the connectors don't snap off if you don't use a sleeve.

For example, look at the following image: https://img1.etsystatic.com/000/0/5914559/il_fullxfull.168287001.jpg below.

Notice how the line cord is nice and round and is the exact same color as the phone? Personally, I find that more visually appealing than a flat gray line cord. I don't know if it's just me. But for me, phones with 4-prong plugs were the most visually appealing, since the cord itself was part of the "decor".

Was there really a technical reason that the modern RJ11 cords/jacks were phased in and 4-prong was phased out?

[TelePlay]

Was there really a technical reason that the modern RJ11 cords/jacks were phased in and 4-prong was phased out?

Let me take a guess, R&D developed a better and cheaper way to mass produce more cost effective production solution that was needed to keep the total cost of the phone down as well as to keep the price of the item competitive in the market.

[bellsystem]

To keep the price of the phone down in the market? This was the 70s - Bell was a monopoly.

[TelePlay]

To keep the price of the phone down in the market? This was the 70s - Bell was a monopoly.

Somebody paid for the phone (Bell up front with the cost recovered in monthly phone bills and phone rentals) and even the Bell System had to keep their costs under control to turn a profit after paying their plant, equipment, supplies, power, water, heat and the largest of all expenses, their employees wages. Everything Bell did from day one to make the current product better for less money. The cheaper the mass production of anything could be kept the cost down. There is nothing free in a monopoly, everything has to be paid for with enough left over to pay stock holders a dividend or risk the loss of huge amounts of company value.

I think you need a course in economics, accounting, and business planning (creating a product in concept, determining production costs, factoring in the cost of plant and equipment, overhead and wages) to see how much it costs to make something and if it can be sold (monthly phone bills in this case) at a price acceptable enough to customers to justify them paying their hard earned money to have a phone in their house. There was a time when only one or two places in a town would have a phone and everyone would go down to the store to make a call. Prices came down and more people could afford the monthly bill. The world did not begin in 2000. Historical knowledge and contemporary knowledge of production, marketing and sales is far beyond the simple excuse of they having a monopoly.

There is no free lunch anywhere anytime, everything has a cost and if a company can't make enough to pay their bills, they go out of business.

[twocvbloke]

Smaller volume of plastic and metal, cheaper to make, faster to fit to wires, cheaper to use, up to 6 conductors in one package, cheaper to stock...

There's also the fact that it became a universal global standard too, whereas before the modular plug, each country and telephone supplier used their own standard which was incompatible with another, so it helped unify the communications world...

[Victor Laszlo]

BS:  I think my colleagues here are missing the point.  No one has mentioned the difference between the concept of "portable" phones and "consumer replaceable" phones.

The 4-prong plugs/jacks (which I agree are very well designed and easy to manipulate) were originally designed to allow a rental phone to be moved from one location in a house to another. There wasn't much of a savings, because the subscriber still paid a monthly fee just for the privilege of having more than one jack.  There was also a requirement that the house be equipped with an external ringer, so that at no time would an incoming call be missed. Answered calls = money.

On the other hand, the modular concept was designed during the decay of the original Bell System (a time in history that seems to interest you) into more of a consumer-oriented industry. Cost savings played a large part. Being able to UPS a handset cord to a subscriber, who could replace the cord himself, for a buck or two, rather than rolling a truck with a Union member, making in today's money $50 per hour, was a huge savings.

Yes, the guys are also correct; it had to do with the advent of the unregulated phone industry that was soon to come. All part of the evil scheme to bust up Ma Bell.

[twocvbloke]

BS:

I have to say, that's a rather unfortunate abbreviation, cos I didn't think "bellsystem" when I first read it..............

[bellsystem]

Well it's nice to see that there are others who thought Divestiture was a terrible mistake. And I can see how 4-prongs would have been considered portable rather than consumer replaceable. More flexible than hardwiring but not as flexible as modular cords.


Still, I occasionally see phones online that were originally 4-prong, and then a refurb. fits it with a modular cord and gets rid of the 4-prong cords. Part of me dies every time I come across something like that. Personally, I think the 4-prong phones look nicer, and I'll have some of the jacks in my home be 4-prong to allow for easier connection - hopefully all the 4-prong phones don't eventually get converted to modular!

Requirement for an external ringer? In "The Rape of Ma Bell", the authors argue that phone companies (post-Divest.) should mandate having one non-modular phone that is hardwired to avoid missing calls. Was that also a requirement, or just the external ringer?

@Twocvbloke - No worries about the abbreviation. I have a website called "The Bell System" which I just abbreviate as TBS when taking notes.

[TelePlay]

I'm not sure if we've climbed through the looking glass once again with this topic but regardless, I'm certain we aren't in Kansas anymore. Maybe it was H.G. Wells invention hitting any one of the many Ori worm holes that while fortunately miss the Tardis just happen to hit selective topics on the forum and with way too frequent regularity.

[AL_as_needed]

To keep on track....

Even RJ11 connectors are falling by the way-side as we see more and more advanced and more digital hard wire phones (mainly in commercial settings). As Twocvbloke said, they could simply fit more connections in a smaller space. Technology tends to always move towards miniaturization to that end. Just looking between say a 202 and a trimline, the size of components is  night and day. A modern office desk set has all or more functions than the WE call director and takes up no more space than a WE 500. It is the unfortunate side of economics in a capitalistic open-market system; cheaper, lighter, more disposable, lower production cost, profits.....

I too like the color matching line cords, especially on my pink princess (oh yeah, im a tough guy). It shows there was some thought put into how these things looked and an attempt to make them visually appealing in an era where there were few "extras".

[compubit]

I'm also going to throw out two

1) Safety (with regard to voltages) - with the Modular jack, it's almost impossible to "get zapped" during the ringing cycle with a modular plug, as there is effectively no way to get between the plug and jack.
2) Plastic "reliability" - many of us have had the color-matching 4-prong plugs break (overtighteneing the screw, getting dropped, etc.), effectively requiring a new cover.  The modular plugs can take a beating and are no worse for wear.

What it comes down to is money. As mentioned before, modular cables are user replaceable (mail a replacement rather than sending out a union truck), the Carterphone decision probably had an effect (may as well have Bell design the standard connector, so that others pay them royalties, vs. them paying someone else), and the entire commoditization/consumerism of phones themselves (this is when the Bell Phone Center Store/GTE Phone Mart picked up, allowing a wider variety of phones that users could self-install, plus they could market the entire Design Line series - meaning more $$)

Yes, having the Bell System in place was nice, but time marches forward, as does technology (BTW, the only land-line based phones at Best Buy yesterday were cordless sets - nothing wired...). The cell phone networks and VoIP have effectively replaced the landline - I don't have a landline at home, as it would cost me $50/mo ($43.04 before taxes) - and that's just a voice line, no Internet (price jumps to $50 for DSL and goes up from there). I do have VoIP lines, where I pay $0.85/month per phone number (plus outgoing usage at $0.009/minute), for 5 minutes each year I use the landline - and these are more for fun. (For example, if I'm selling something and need to give out a phone number I can stand up a number, give it out, and when the item is sold, shut it down, and not get any spam calls.)

Everything else is on the cell...

J

[trainman]

Plastic get brittle with age. when those 4 prong plugs were new, they didnt routinely break from tightning the cover crews. thatcoomes with age.

[Alex G. Bell]

Plastic get brittle with age. when those 4 prong plugs were new, they didnt routinely break from tightning the cover crews. thatcoomes with age.

Au contraire!  The thin gray plastic used on modular jacks is drying out and crumbling spontaneously in many examples I've seen.  In some sets they fall apart due to the tiny stress produced by removing or replacing the housing.  I've never seen a 4 prong plug self-destruct.

Modular jacks also have an electrical creepage path problem.  When used outdoors at Network Interface Devices in humid climates the linear distance across the insulating material is insufficient due to the small size, causing electrical leakage to result from accumulated dust and dirt absorbing moisture from the air.  This can cause the gold contacts to turn green with corrosion (verdigris is the formal term).

The fundamental rationale for modularization was for installers and repairmen to carry phone bases without handsets, even without housings, and marry a housing and base (wall or desk), matching color handset and cords of the selected length to build a telephone set meeting the customer's wishes at the job, stocking fewer different phones in the truck and field "locker" supply sites.

The secondary rationale was for easy replacement of cords for maintenance during repair visits.

The flat cords also provided for use of insulation displacement connections since the conductors have a fixed geometry and arrangement at the ends.  This facilitated manufacture by allowing a single plug to be applied to each end instead of multiple separate spade tips plus a strain relief.

[compubit]

Au contraire!  The thin gray plastic used on modular jacks is drying out and crumbling spontaneously in many examples I've seen.  In some sets they fall apart due to the tiny stress produced by removing or replacing the housing.  I've never seen a 4 prong plug self-destruct.

I haven't run across any original WE modular plugs that have broken.  Now the clip on the plug is a different story...  I did have some early GTE modular plugs that have fallen apart.

Modular jacks also have an electrical creepage path problem.  When used outdoors at Network Interface Devices in humid climates the linear distance across the insulating material is insufficient due to the small size, causing electrical leakage to result from accumulated dust and dirt absorbing moisture from the air.  This can cause the gold contacts to turn green with corrosion (verdigris is the formal term).

Irony of ironies - I just received a Stromberg 2511 that looks like it's been sitting in a storage unit in Galveston, TX or Miami, FL, and the modular plug has verdigris (no visible gold) -and is starting to disintegrate.  So far I've been able to rescue the case and handset - not holding my breath on the line-switch mechanism... (and i suspect the tone pad is toast, as it has a good amount of rust on the ferrite cores...)

Plastic get brittle with age. when those 4 prong plugs were new, they didnt routinely break from tightning the cover crews. thatcoomes with age.

Good to know, but now I treat the ones I have very carefully - I've broken at least two along the way...

[Alex G. Bell]

Au contraire!  The thin gray plastic used on modular jacks is drying out and crumbling spontaneously in many examples I've seen.  In some sets they fall apart due to the tiny stress produced by removing or replacing the housing.  I've never seen a 4 prong plug self-destruct.

I haven't run across any original WE modular plugs that have broken.

I was referring to the jacks, but now that you mention it, plug latches (keys) are a problem too.  I've replaced countless plugs because the latches broke off just from fatigue.  So called "live hinges" (thin plastic intended to flex) die!

Aside from failing in normal use, they are inherently prone to snagging on other cords and break off when re-routing cords.  The modular system was not well thought through in many respects. 

Another is the stupid sequential numbering of the pins from one end.  If they had numbered them odd/even outward from the center like Strowger switch shelf jacks had the insight to do around 1900 the contact numbers would match when a 6-contact plug is inserted in an 8-contact jack, something which is sometimes necessary.

Now the clip on the plug is a different story...  I did have some early GTE modular plugs that have fallen apart.

Irony of ironies - I just received a Stromberg 2511 that looks like it's been sitting in a storage unit in Galveston, TX or Miami, FL, and the modular plug has verdigris (no visible gold) -and is starting to disintegrate.  So far I've been able to rescue the case and handset - not holding my breath on the line-switch mechanism... (and i suspect the tone pad is toast, as it has a good amount of rust on the ferrite cores...)

Good to know, but now I treat the ones I have very carefully - I've broken at least two along the way...

I've never seen ferrite rust.  I didn't think it was possible.