Telephone Identification, Repair & Restoration > Technical "Stuff"

102 versus 202

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I wrote this a while ago, and have gotten it to a point where I can post it here.  Dennis Markham was kind enough to proof it, and my original writing combined the 102/202 topic with the topic of subsets and was too long.  This is even kind of long, but is shorter than it was.  I think Dennis was talking about making this a sticky topic that can be used for reference rather than a thread.  However, before it does become a sticky topic, I would surely welcome additional comments or suggestions, and or maybe technical corrections to dates.  My bibliography was mostly from memory, but also from Ralph Meyer's book "Old-Time Telephones! Design, History, and Restoration", and from Larry Wolff's Book "Desk Telephones of The Bell System The years 1875 to 1955"

Here it is:


What is the difference between a 102 and a 202?

Many people come into the hobby trying to learn about some of the early Western Electric telephone models.  The earliest handset models for Western Electric were called “desk sets” and they had to be matched up with a “subset” (Subscriber set) in order to function.  The combination of the desk set and the subset is what made the complete telephone.

The desk set usually sat on the desk and had a felt or leather covered bottom.  It consisted of just the body called the “mounting”, the handset, a dial (if it were for dial service), and the switch that is activated by taking the handset off the cradle.  Other than the handset cord and the cord that connects the desk set to the subset, that is all there generally went into a desk set.  Sometimes there was a couple of additional items connected to the dial to prevent interference to nearby radios sometimes caused by the dial pulses emitting radio frequency interference.

The body or “mounting” of these early desk sets had a letter designation.  The “A”  or “A1” mounting was the first ever handset and cradle model Western Electric produced.  It was only made for a year or so around 1927.  Its base was round, and resembled a candlestick base in its construction.  Not only were they made for a short period of time, but few were made, and many were used in test environments to test the new concept of a handset in the USA.  These tend to be very pricey due to the relative scarcity of them. These would be correct with the early E1 handset which would have had the seamless handle and seamless handset caps, but would have also had the early “bullet”, or barrier button style 395A transmitter.

In 1928 or so, Western Electric replaced the A1 mounting with the slightly more streamlined B1 mounting.  Its life went for about 2 years until about 1930.  In the meantime, many of these were made, and are not uncommon items on E-Bay.  These also had a round base, and originally would have come stock with the same handset as the A1 model.  Both the A1 and the B1 would have come originally with a #2 dial that has the finger stop mounted to the side of the dial.  The dial mounted on the surface of the desk set mounting and was not recessed.

From about 1930 until 1938, the model being produced was the “D1” mounting.  It has an elliptical base, the dial mount is in a recess, and the dial needed is a #4 which does not have the dial finger-stop mounted externally.  It has a slightly lower profile and height than the B1 mounting, and the elliptical bas made for more stability while dialing.  This base had a more flush dial mounting due to the recess.  It would probably have been equipped with an E1 handset with seams along the side, and around the receiver and transmitter caps.  The handset would have contained a much improved F1 transmitter element retrofitted to fit in the E style handset.  Later models of the D mount, and even some B mounts were retrofitted in the field or in the refurbishing shops with complete F1 handsets in the late 1930’s

So, why all this talk of A, B, and D mountings.  What about 102 versus 202?

The 102 versus 202 designation has nothing to do with a model of the phone body itself or the way it looks.  102 simply means that the desk set was connected to a sidetone subset, and a 202 was connected to an antisidetone subset.

What is sidetone and what is antisidetone?

Sidetone it the term given to the fact that when you talk or blow into the transmitter, you can hear your own voice in the receiver.  Some sidetone is good, but too much is detrimental to carrying on a comfortable conversation over the phone.  Users of sidetone phones would naturally lower their voice, which would cause problems on connections over longer distances from the central offices.  Sidetone sets were also a problem in noisy environments, like a factory or a busy office.  Too much local noise would come back into the local receiver and make it hard for the person to hear the person on the other end.

Antisidetone circuits were developed in the late 1920’s and rolled out in the 1930’s.  They are completely a function of the subset and not the mounting.  Therefore, the B1 and D1 mounts could be connected to either subset type.

The circuit designation for sidetone was 102 and the designation for antisidetone was a 202 circuit.  That is where the 102 and 202 designation comes from.

Why do people on E-Bay and others commonly refer to the round-based B1 mounting as a 102 and an elliptical D1 mounting as a 202?  I feel that most of the B1 mountings when first placed in service were connected to sidetone subsets, and most later D1 mountings that came out at about the time antisidetone came out were just associated with the 202 type subsets by default.  Besides, the difference in physical appearance makes for kind of a convenient visual differentiation.

Next, a discussion about the subsets.


Nice to see I'm not the only one who makes long posts : - )   Excellent job there. 

Proofread: typo: paragraph beginning "From about 1930.." search for the word "bas" that should be "base." 

Re. Sidetone:  Feel free to use this wording if you like:  "Sidetone is audio such as speech from your transmitter that is heard in your own receiver.  One way to hear this is to blow gently into your transmitter and listen for the noise in your receiver.  If there is too little or no sidetone, the phone sounds "dead" and you are likely to talk loudly.  With too much sidetone, you hear your own speech so loudly in your receiver that you are likely to speak quietly, in some cases too quietly to be heard.  Just the right amount of sidetone makes the phone sound "live" but not too loud, so you are likely to speak at the right volume to be heard clearly."


Why I used the terms 102 and 202 indiscriminately until I hung out here a while:

First phone I ever had was a 500 set.  Then I ran into the 302 but initially thought of it as a "300" by way of similarity to 500.  Then I learned that the correct designation was "302."   Then I found the D1 referred to as a 202, and the B1 referred to as a 102, and those numbers stuck in my head because they seemed the logical predecessor to 302. 

So the numbers 102 and 202 are "contagious memes" that I think propagate due to their similarity to 302.  And the way to fix that is simply for enough of us to say B1 and D1, and use the terms correctly, that those memes propagate until the incorrect usages dwindle. 


Excellent topic!

Since this will be a reference, it's worth the time to check the BSPs for nomenclature.  As I recall, the Bell System was somewhat obsessive about using "desk stand" for the upright phones with separate receivers we commonly call candlesticks and "hand telephone sets" for early phones that used handsets.  Did they also use "desk set?"

The "hand set mounting" was the part of the set that held the handset, and in this case was marked with a code beginning with A, B or D.  Note that there was a number after the letter to indicate a variation -- up to at least D10.

You probably want to avoid the complexity of describing each variation, but can refer to the styles as A Type, B Type or D Type, rather than using the most common variation (A1, B1, or D1).  Your comments on sidetone versus antisidetone apply equally to all variations.

A wrap-up sentence could include the notion that due to the ambiguity of the terms 102 and 202 collectors prefer to use the hand set mounting code when describing the physical appearance of the phone.

[I just did a quick check of some of the BSP index documents to confirm the above --
  C12.101, IC and 502-000-000, I34.  Also see C38.323 I2 and C32.164 I1.]


This is a great thread and I learned a lot from it, which is why I joined this forum in the first place.  Until now, I had no idea what sidetone/antisidetone was but obviously just got a bit of education here.

I'm sure there is a thread here somewhere but can someone please direct me to what desktop sets match which subsets?  I'm trying to learn this as I am restoring my first phone but want to expand past the phone that I am currently working on.  I'd appreciate a point in the right direction.




That is a good question, but I don't think there is any right answer, at least not all the time.  There were so many odd-ball configurations that an all-inclusive list would be difficult.  One can kind of go based on the dates of the phones and whether they are sidetone or antisidetone and match the phone to an appropriate subset of the same time period.

Since subsets were mounted on the customer's wall, a subset used for a non-dial candlestick, may very well have been left in place when changed out for a dial desk set, and left that way for years and years.

Add to that complexity that two of the subsets, the 534 and the 634, which were large, heavy and had a metal cabinet were re-made as a 584 and 684 using smaller, lighter parts and a bakelite cover.

So, generally, one has to go based on the year.

According to Ralph Meyer's book,  Western Electric subsets were introduced as follows:

295  Wooden, sidetone 1902  Used for any candlestick of the time.
334 Metal version of the 295 introduced in 1912 and used for the same phones
534 Slightly smaller somewhat improved circuit.  Sidetone introduced in 1918 during the realm of the candlestick, but would have been used on the A, B, and D mount telephones connected as sidetone, and the 20, 40, and 50 series candlesticks
634 Antisidetone version of the 534 above, and indtroduced in 1930 when antisidetone circuits came to be.  Same metal cabinet, and would have been used for the B and D mount phones connected as antisidetone and the 150 series candlesticks
584 A smaller and lighter, more streamlined version of the sidetone 534.  Introduced in 1930, presumably as a retrofit for older sidetone phones needing a new subset.
684 An antisidetone version of the 634 introduced in 1930, and an equivalent but smaller circuit as the 584.  Used for the B and D mounts and 150 series candlesticks.

Other uses of subsets would have been for the space savers and pay phones, and were made well after the 302 was introduced in 1938 which eliminated the need for subsets in most cases.  The 685 subset which is based on 500 technology using the 425B network was highly used in payphones of the 50's and 60's.

It should be noted that a sidetone phone can be connected to an antisidetone subset, but the phone will still function as a sidetone phone.  An antisidetone phone can be connected to a sidetone subset, and the extra black wire simply taped and stored.  This will also function as a sidetone phone.

I think this is an area where us as collectors have some leeway in choosing a subset to mate with the phone, and other that getting it correct as to the period, there are no hard and fast rules to observe.  This is consistent with how these were connected and serviced at the time.  During those years, and particularly through the depression, the phone company was likely to connect a phone to any subset that worked.

All of this is my opinion, of course.


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