BTMC 2652

BTMC 2652
BTMC 2652
BTMC 2650
BTMC 2650

Designed in 1912 by BTMC (Bell Telephone Manufacturing Cie) in Antwerp, this telephone was produced by many companies throughout Europe.

The BTMC 2652 (and the wall version 2650) is one of the first telephones designed for automatic telephony in mind (rotary dial) as well as for a certain level of mass production. Until this telephone was introduced, existing telephones were adapted to automatic telephony, often by just bolting a bracket with a dial on the housing. The design is from 1912, when just at the dawn of automatic telephony in Europe, when telephones were not a very common occurrence yet.

In a time when not many people had a telephone and automatic telephony was in just coming of age, this model prepared the way for large scale telephone subscription and the use of the rotary dial.

History and development

ZBSA 11
ZBSA 11

Although automatic telephony was first practically applied at the end of the 19th century by mr Strowger in the USA, Bell and Western Electric stayed committed to manual exchanges until the end of the 1920s. In Europe there was more effort to automate the telephone networks early on, fuelled by developments in Germany (Siemens) and Sweden (Ericsson).

This led to the development of the BTMC 2652. In 1912 there were hardly any automatic exchanges in operation. The first automatic exchange in operation on the public network manufactured by BTMC was the one in Hull, in 1915.

Often first semi-automatic telephony was introduced, whereby the operator dialled the desired number. Because of this, this phone was available with and without a dial, where in the latter case a dial could be retrofitted very easily.

So the BTMC 2652 could be used on manual, semi-automatic and fully automatic exchanges.

Western Electric 396 A
Western Electric 396 A

Because Belgium was overrun by the Germans in 1914, production of this phone was interrupted. Western Electric continued production in Hawthorne, USA, where they manufactured more or less the same model in form of the Western Electric 396. After WW1 production was resumed in Belgium and this phone would remain in production until the end of the 1920s.

Not only was it manufactured in Belgium, but also at other WE/ITT plants. It was for example also produced in Spain and Norway, with minor local variations.

BTMC 2712
BTMC 2712

It is unclear whether this telephone actually was produced with a dial before resumption of production in 1919. On the exchange in Hull that was put into service in 1915 English candlesticks were used. Possibly some were produced with a dial for private installations before 1919.

In 1927 the successor of the phone was introduced, the BTMC 2712.

Design and construction

Typical fort his period this phone basically is a metal box with a large cradle assembly on top. The cradle assembly is

Ericsson DE 500
Ericsson DE 500

so high, as to accommodate the speaking tube. See also this photo of an Ericsson telephone with such a speaking tube.

The dial, in case there was one, was mounted on a separate bracket on the outside of the housing. This bracket was fitted between the stem of the cradle assembly and the housing. On versions without the dial a filler ring was fitted, so that a dial could be fitted very easily.

This telephone is a fully integrated telephone, which means it can be used without any additional peripheral equipment on a telephone line. Many other telephones from this period require for example an external ringer or even a subset, which contained the coil, ringer and capacitor.

BTMC 2652 binnenkant
BTMC 2652 binnenkant

The BTMC 2652 already has a speaking coil, improving the sound quality. This coil prevents so-called side tone, the interference from the microphone on the incoming sound.

The telephone was based on an American subset made by Western Electric and the lay out of the components is derived from that.

Some effort was made to use as many of the same components for the wall and desk telephone. This was however limited to the technical components of the telephone.

BTMC Catalogue 1924
BTMC Catalogue 1924

There are many versions of this telephone, and I have been able to collect a number of them. No only are there versions with and without a dial, but also wall models with internal direct current ringers, blinkers, multi-line versions with selector keys, versions with and without carrying brackets on the stem of the hook switch assembly and there are also 2 kinds of closing mechanism of the housing: with a clip and with a screw. Of course most of these variants have a different model nr.

What kind of phone do I have?

BTMC 2652 diagram
BTMC 2652 diagram

These telephones are hard to determine and to date. There are very few markings on them, that give information as to their origins and manufacturing date. In many cases there isn’t even a BTMC label on them nor is there a label with the model nr. Often only the diagram betrays that it was made by BTMC. These were white on black, instead of black on white for the ones from other producers. Dating them is even harder: hardly any of the parts carry a production date. If you are lucky there is a date on the capacitor.

The BTMC 2652 today

The BTMC 2652 and most of its variant scan still be used on the modern telephone network. Even on a VOIP-modem this telephone can be used. Transmitting, receiving and ringing the bell is still possible, although dialing with a rotary dial is in many case not supported any more. But if you use a pulse-DTMF converter the phone can be used normally for dialling out.

I have had my own BTMC 2652 connected for a while and it worked perfectly. Possibly this model gives off a ting (bell tap) if another telephone on the line goes on or off hook. That is normal for a telephone from this period.

Verbogen opleggewei
Bent cradle

With the passing of time a number of problems and issues have come to light, beginning with the most troublesome: the cradle fork is bent. It is a vulnerable part, because it protrudes very highly it often gets bent out of shape. It is not easy to repair. Be very carefull bending it back, as it easily snaps off.

Typical for these telephones is that the little nuts loosen, especially those holding the bolts for the components on the base plate. This results in missing bolts and nuts, causing the components inside being loose and in the worst case causing damage.

Of course there is more or less oxidation of parts. Most of it can easily be removed, fortunately, but in severe cases the phone needs to be repainted and renickeled. That does affect its originality of course, as does replacing worn cords with new ones.

Typical for this model dial, that can also be found on other telephones, is that the small cap with the label window is missing. This cap has now become a rare part.

BTMC versie met blinker en knop
BTMC versie met blinker en knop

Although this telephone was once a common model, they are not easily found nowadays. Most of them were, after decommission, destroyed by the telephone companies. A good specimen is rare indeed.

On top of that this model seems somewhat forgotten. It is less well known than its counterparts from Ericsson and Siemens and because of that undervalued and less sought after.

 

6 Comments

    • Hi Vincent, yes Electrisk Bureau in Norway made their own version of this telephone. Earlier versions are almost indistinguishable the BTMC design.
      Electrisk Bureau was part of Standard Electric and later ITT when these were made.

  1. I have 2 7001E dials. They are extremely compact, and almost impossible to service.

    One of them was pretty ruined, I had to make anew number plate. The cam wheel was not good, so I used the dremel and made the last pulse equal to the others. (would not have done that with a dial I could have saved in original condition, it had already past that point) Adjusting the spring set as much as possible so I got as long breaks as possible and it was accepted by the dialgizmo.

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