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Daniel Zuperdee's time-line history of the development/changes

Started by Western Bell, December 11, 2019, 01:44:13 PM

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Western Bell

Quote from: david@london on December 11, 2019, 08:32:13 AM
Daniel Zuperdee's time-line history of the development/changes in production detail of the WE500....


By the late 1940s, research and development in electronics and in plastics had come far enough so that Western Electric (the manufacturing division of AT&T) felt it was time to replace the venerable old 302 that had been in production since 1936.

​The Western Electric Model 500 telephone was the standard desk-style telephone set used by American Telephone & Telegraph (the Bell System) in North America from the late 1940s through the divestiture of AT&T in 1984. The last phone of this type was made by Cortelco (formerly ITT) in about 2005.

​The model 500 went into production in 1949, and was initially available only in black, with a plastic housing and dial face, straight handset cord, and a bakelite handset. This finally changed in 1953, when four colors were introduced. Soon, coiled handset cords would become standard. Over the years, colors would come and go.

Although some various production changes and tweaks would occur over the over the years, the basic design remained almost totally unchanged from 1949 right up through the divestiture of AT&T in 1984. Production continued after divestiture under the name AT&T Technologies until 1986, when the Indianapolis Phone Works plant was finally closed, and production moved offshore.

​The vast majority of telephones made by Western Electric were made for the Bell System, although they also made special models without Bell System markings for independent phone companies. Western Electric also made some special models of the 500 for military and government use.

Many millions of Model 500 phones were produced and were a familiar sight in almost every home in America. Many 500 phones are still in use today thanks to their durability, low prices, and ready availability.

​The phone's construction made manufacture and repair simple, but also made possible a large number of derivative models with different details and features. A touch-tone version, the Model 2500, was first introduced in the 1960s, and is still produced today by several manufacturers.

The original WE Model 500 was designed by the Henry Dreyfuss industrial design firm, and was the result of several years of research and testing, and was introduced in 1949.

The 500 replaced the Dreyfuss-designed Western Electric Model 300 series, and improved upon several areas of design that were problematic in the earlier models. For example, the Model 302 utilized a porcelain-coated dial plate, with the numbers printed inside the finger-holes. After years of use, the printed numbers and the even the dial plate's porcelain coating would wear off. The design of the 500 corrected this by moving the numbers outside of the finger holes, and molding them into the plastic instead of printing them on the surface. This numbering arrangement also had the benefit of reducing the number of mis-dialed calls.

During its long service lifetime, the 500 was not without critics. The phone's blocky and uninspired styling was considered merely adequate in 1949. The phone's internal components remained little changed over the years, and the sheer weight of the phone and its handset were an obstacle for some users, notably the elderly and the physically challenged.

​By the early 1960s, European phone designs offered cleaner lines, lighter weight and more ergonomic handsets, and made the 500 look positively ancient in comparison.

Originally, the 500 was available only in black and had a rotary dial with a black-painted metal fingerwheel (black remained the most popular color throughout the model's production, and the Model 500 has been affectionately nicknamed by some as "the black brick"). Within a few years the Model 500 began to be made in a variety of colors, and the metal finger-wheel was replaced with a clear plastic wheel. The 500 was also the first phone to use the "G"-style handset, which remains in use today.


Telephones derived from the basic Model 500, using some if not most of the same components, included the Model 554 wall-mounted phone and the 1500, 2500, 1554 and 2554 touch-tone phones. In the mid-1950s, in order to avoid disposing of older phones, Western Electric manufactured a 500-style plastic replacement shell to update the appearance of the 302, calling it the Model 5302. This model used the internal components of Western Electric's earlier Model 302 phone.

Because most phones used in the Bell System were owned by the Bell System, which was responsible for keeping them working, the Model 500 was designed to minimize repairs. It was extremely rugged and reliable, and intended to last for decades. The 1940s-era technology of the 500 makes extensive use of solid metal components and point-to-point wiring, and most components are simple to remove and replace.

Originally the line cord and headset cord were secured by screw down terminals at both ends, with a strain relief anchor. Tubular rubber covers at the ends resisted tangling and wear. The line cord (the cord that connected a desk phone to the wall) was originally the same color as the phone. In approximately 1973, the line cords were changed to a neutral gray color and went from round to flat. In the late 1960s a need arose for a plug and jack system. Initially, the phones were equipped with "hard-wired" cords, but plug-ended "modular" cords ware introduced in the 1970s, starting in Chicago.

In the 1980s AT&T started selling phones outright to the public through its then-new American Bell division, instead of just renting. AT&T found itself unable to compete either in price or in selection, and eventually closed its telephone manufacturing plants and retail stores.

Other Model 500 manufacturers

Beginning in the early 1950s 500-style phones were also made under license by ITT Kellogg (now Cortelco), Northern Telecom (now Nortel Networks) and Stromberg-Carlson (later Comdial).

Timeline (some items need verification)

First year of production

The bases are date-coded in the form, "mm-yy," where mm = month, and yy = year.

Initial models use a 425A network, together with a model 311A equalizer unit.

Just like Henry Ford, you can have whatever color you want, as long as it's black. All black sets have plastic housings, matching black plastic hookswitch plungers, bakelite model G1 handsets, and a model 7A rotary dial, with a black painted metal fingerwheel.

The faceplates on the dials are clear, with the underside painted black.

Straight handset cords are standard.

The G1 handset has a groove running the length of the handset on each side, similar to the F1 handset and the later E1 handsets. The grooves were to remove the mold mark from the casting.

The cavity for the transmitter cup has two prongs in it for holding the cord, and the back of the plastic cup is plain, with no prongs.

The date of manufacture of the housing is printed in ink along the inside front.

Shifted from the 425A network with a separate model 311 equalizer (using the tungsten-element) to the improved 425B network, which had an integrated equalizer, using varistors. Special-purpose models like the 500J/K/T continued to use the 425A network without an equalizer for a few more years.

Shifted from clear dial faceplates with black paint to double injection-molded faceplates, which have black plastic on top, and white plastic letters/number insets that are part of the backing.

The prongs that hold the handset cord inside the cavity are moved from the bottom of the cavity onto the bottom of the plastic transmitter cup itself.

Four colors are introduced for the first time as a premium option:


Moss Green

Dark Gray

Cherry Red

All of these colors come with straight neutral gray handset and line cords, clear plastic plungers, a colored plastic model G3 handset, and a model 7C dial with an open-center clear plastic fingerwheel.

Black sets continue to have black plastic plungers, a model 7A dial, with a black painted metal fingerwheel, and a black model G1 bakelite handset.

Four more colors are introduced:

Mahogany Brown

Dark Beige

Pastel Yellow

Dark Blue

All of the available colors come with straight gray cords, except brown and ivory, which come with matching straight colored cords. Some yellow sets also came with matching colored cords.

Colored sets are also now available either in full color, or two-tone (colored housing, but with a black dial face and handset).

Shifted from 7A to 7D dial on black sets (?) The 7D dial is nearly identical to the 7C dial, except for having screws instead of die-stamped lugs holding the gear frame; and the governor on the 7D dial uses a spiral spring instead of a coiled spring on the centrifugal weights.

Coiled handset cords are now available as a premium option.

Coiled handset cords, which were previously a premium option, are now standard.(?)

Dark gray, dark beige, and dark blue are discontinued, and replaced with light gray, light beige, and light blue. Mahogany brown is discontinued on residential sets, but stays around a bit longer for business phones (keysets). Brown was brought back in the 1980s.

Pink and white are added, making a total of nine colors.

Dial mounting brackets now have 2 mount points instead of 3. (?)

Handset cords are all coiled and match the phone body colors. (?)

October 1958
Shifted from triangular leather feet to triangular neoprene feet.

May 1959
ABS-based "hard" plastic is phased in for colored sets. Black sets continued to be Tenite until 1964/5

The date of manufacture on the housing is now molded into the plastic near the cradle, instead of printed in ink along the front edge.

Production of colors reaches: red 4%, yellow 7%, light blue 5%, pink 12%, white 27%, light beige 22%, green 7 %, light gray 5% and ivory 11%. These percentages are of the total 67% of production, so about 33% of production is still black.

The die-cast aluminum top on the 7C/7D dials is changed from a complete circle to a point on top, and the gear frame is now die-stamped together, instead of held together with screws as before. (?)

The resonator shells on the C-type ringer are now plastic instead of metal. (?)

Production of black G1 bakelite handsets gradually shifts to black G3 plastic handsets. This transition is completed in 1965.

Shifted from triangular neoprene feet to round feet with ribs.

Shifted from 425B network to 425E network. Apparently the only difference between these networks is a screw-on "C" terminal instead of a soldered one.

Turquoise is added, for a total of eleven colors.

Transition to hard plastic is completed.

Transition to black G3 plastic handsets is completed.

Black sets are finally brought in line with the colored sets. All of the colors thus now have hard plastic housings, plastic G3 handsets, clear plungers, and closed-center clear plastic fingerwheels.

The #7-series dial is replaced with the #9-series dial on all colors. The #9-series dial is designed with an emphasis on quieter, smoother operation, and greater cost-effectiveness. Also note that the faceplates for #9-series dials are NOT interchangeable with the faceplates for #7-series dials. Unlike the #7-series faceplates, which are held in place by screws, the #9-series faceplates are held in place with a twist-on spring metal retaining ring.

Shifted from black paint to yellow cadmium plating on the bases.

The round neoprene feet are now flat instead of ribbed.

The bases and handsets on all models made for the Bell System are now stamped with the words, "Bell System Property, Not For Sale."

Shifted from 425E network to 4228 network. (?)

Shifted from hardwired to modular line/handset cords. (?)

Changed the style of date coding. Instead of "mm-yy," it is now "yyddd," where yy = year, and ddd = the day of the year.

Shifted from the old model 9C dial to a new model 9CA dial. The new model has plastic bearings for the gear shafts, and a plastic shell around the metal governor drum. The faceplate is now held on directly by plastic lugs molded into the dial frame, instead of the metal retaining clip used on the previous model. Also, the traditional screwed-on fingerstop has been replaced with a clip-on fingerstop, which also acts as a way to secure the faceplate in place under the plastic holding lugs.

Shifted from the 4228 network to the 4293 network. The 4293 network is similar to the network found inside the Trimline phones. Compared to the 4228, it sacrifices some performance in favor of lighter weight and smaller footprint, which were important for the Trimline, as well as lower cost.

Introduced customer-owned models with "CS" prefix. They are pretty much identical to the traditional rented models, except that they lack the "Bell System Property, Not for Sale" markings. (?)

Production under the Western Electric name ceases, with the divestiture of AT&T. Production of customer-owned "CS" models continues a little bit longer under the "AT&T Technologies" brand.

Color changes.

Shifted from metal screws and brass inserts to self-tapping screws directly into plastic to fasten the housing to the base. (?)

Production of the traditional Western Electric model 500 ceases when the factory in Indianapolis is closed, and production is moved overseas.

(end of 500 information - attached pdf has more)