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From the March 1999 Singing Wires newsletter

50 Years Old, And Still Going Strong

By Bruce Crawford

Not only does 1999 mark the last year of this millennium, it is also the 50th. anniversary of the world's most popular telephone, the 500. According to an article that appeared several years ago in NEW YORK magazine, Western Electric (and its successor, A.T.&T.) manufactured more than 165 million basic 500 sets! At the peak of production, business telephones alone (which used 500 set components) represented greater than one in every ten sets made! On top of that. Decorator phones (from the Princess of 1959 to the 1970 decorator lines) all used 500 set components.

Experimental models of the 500 were supplied to Bell System executives as early as 1947 (according to an engineer from Bell labs, with whom I spoke many years ago). However, none of these early models seem to have survived. The earliest "production" model of a 500 that I had in my possession dated III49, which I believe meant the first quarter of 1949 (later sets were dated with the actual month of production).

As is well detailed in Dr. Meyer's book, "Old Time Telephones!" (Chapter 19, page 199) the circuitry of the original 500 set was quite different from production 1951 or so onward. Current flow regulation (which was intended to balance transmission characteristics regardless of the length of line) was provided by an optional "ballast" lamp. located in a little package called an "equalizer". Although this type of regulation was soon scrapped, British manufacturers used the same type of regulation in their "700" series sets, and this too, was an option. Most manufacturers eventually duplicated the 500 (Northern Electric, because of Bell Canada's Bell System affiliation, was first). One company that never copied the 500 was Automatic Electric. In early years, AECo used a potentiometer to regulate current flow in their type 80 (and this idea was experimented with by the Bell labs in their 1947/1948 prototypes). Eventually, a more modern network was introduced, which used varistors to control the amount of current flowing through the loop.

In order to increase outgoing transmission, Bell engineers decided that the handset should be closer to the mouth, and the original handset (used on the prototypes) was, indeed, shorter. (This handset was almost the same as used on [ITT] Kellogg's original "K-500".) Sadly, as Dreyfuss cleaned up the design, he introduced a flat back on the handset. It was so easy for the user to prop the handset between his/her shoulder and ear (leaving the hands free) that the transmitter eventually slid under the user's chin, thus severely impairing transmission.

It is not unusual to find 302-type sets (and rebuilt 500 look alikes, the 5302) with internal components dated as late as 1956. The reason! The Bell System was slow to adopt the 500....and perhaps with good reason. The main problem seems to have been cost. 500s were nearly 50% more than 302 type sets. The early 500s were plagued with transmission problems, and the ringers were (and remained) less efficient than their 302 predecessors. In the late 1960s, a "U" type receiver unit, as a repair part, was $4.00 each; the 302 "H" type unit (which, by this time was produced in limited quantities net only) was $1.00 less!

Another major problem with the 500 was the original 7A type dial. In order to try to eliminate many of Western's long standing dial problems, the labs produced an extremely high quality, smooth running unit, using some of the principles of AECo's 24 type dial. (The trigger action of the Western 1, 2, 4 and 5 type dials did not have the correct wave form.) However, the next result was a grossly overpriced unit. which, like the other components, contributed to the high cost of the 500. Eventually, a somewhat inferior dial, the 7C (black) and 7D (color) was substituted. This dial was harder to turn, and noisier, and eventually, after experience with the new Princess dial (the #8-type) Western designed a much better dial, the #9.

What really got the 500 off of the ground, however, was color. The Bell System had always been loathe to promote colors, (although, as we all know, they were certainly available, at a hefty premium!). The surcharges for color were changed from a rental fee to a much smaller one time "non-recurring" charge ($9.00 to $12.00); and then the 500 "took off."

The 2500 set, a Touch-Tone version of the 500, was introduced c. 1965. Originally produced in a 10 button version, two buttons were soon added for end-to-end signaling. Originally designated as the Sextile and Octothorpe, these buttons soon became known as the (often hated) "Star" and "Pound" keys. They introduced many of us to a computer world!

500 sets are still being refurbished and re-installed today. Most have been built new, or converted, to modular. Some are retrofitted with an electronic transmitter. Others are refurbished using a superb Asian "carbon-type" transmitter. This unit, coded T-100, replaces the original WECo T-l. (Long time telephone refurbishing experience has indicated to this writer that ITT-Kellogg's version of the T-1, the #75555, was superior to all other North American manufacturers.)

The 2500 set is still manufactured "off shore". All components are (more or less) interchangeable with the original North American product(s). (I've found that the ringers in these sets are slightly less efficient that the original WECo C4A units. This was also a problem with the ITT-Kellogg version.)

I do not know of any product that has lasted as long as the 500, and has also been produced in such large quantity. Despite setbacks, the engineers at Bell Labs, and Mr. Dreyfuss, are to be congratulated for design of an instrument that has stood the test of time, and (in my view) is still a modern appearing instrument. (By the way. the original 500 had a renewable design life of 30 years....I do wonder how many will be around in another 50 years?)