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  • Author Author: jw0752
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Western Electric Interrupter

jw0752

It is always hard for me to not be amazed by the technological progress that has been made in the last 50 or so years. The other day I came across an unusual motorized switch that was made for Western Electric by Raymond Controls Corp. It is a KS-19175-L1 Interrupter. Since Western Electric was the manufacturing arm of the Bell System my first thoughts were that this unique device was part of a telephone system and a little research confirmed this. Here are a couple pictures of the device:

 

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Don't mind the LEDs as these have been added by me to show what the switches in the unit are doing.

 

The mechanism has a small 10 volt AC clock motor that powers a cascade of two gears that each have a cam that engages 6 switches of varied configuration. The motor is designed to turn at 30 RPM and the time for the lowest rotation gear to make a revolution is about 4 seconds. I have jury rigged the switches and patched the circuit board so that each set of contacts is switching one LED. There are 6 switches and 7 LEDs as there is one SPDT configured switch. There is also one switch where a single pole single touch contact actually closes 2 touches. My analysis of the mechanism is that it is not intended to continuously cycle as I have it doing but rather to run a single 4 second cycle when triggered and then wait for another trigger to do it again.

 

A little research indicates that this component was part of a 551C phone system. This was dial phone technology at the transition point to touch tone technology. I do not know exactly what the purpose of an interrupter was and I would be pleased learn more if someone can explain it to me.

 

When I saw what this motorized switch could do with the LEDs it made me think of an Arduino running a simple blink program on multiple output pins.

 

When one considers what a person can do with a smart phone today this communication technology using a motor and a bunch of reed switches feels like it is from the dawn of civilization. One can only wonder what lies ahead for us tomorrow or another fifty years from now. There is no reason to really assume that progress will stop or even slow down. If the step is as great as it has been since 1972 it will be fantastic and certainly beyond my ability to imagine.

 

I leave you with the Western Electric Interrupter running its version of a Blink program.

 

 

John

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  • in reply to Fred27

    That looks like a great documentary, I've watched five minutes of it, looking forward to watching the rest on a bigger screen. The narrator had fun with it too.. "nothing ever stands still.. if it did, we'd be running around covered in woad or something". It's awesome that BT and others documented their work in this way, it was a fascinating time I think - I find anything related to old phone systems interesting!

    I used to work for a company (Nortel i.e. Northern Telecom) that (amongst other things) made key systems (mini-PBXs basically, for apartment blocks or offices), but electronic versions... I had no idea that electro-mechanical versions had once existed.

    you might enjoy looking through bits of this PDF manual, it seems interesting and refers to the 551. From what I can tell, the interrupter was literally used to make and break electrical connections for several general purposes. One purpose being to break up the locally generated ringing tone every few seconds (e.g. if one station called another station) into the familiar ring-ring sound, and another purpose is to flash a lamp to indicate a call incoming on (say) line 1 or 2, or for a hold feature (described here).

  • in reply to shabaz

    Hi Shabaz,

     

    Thanks for the insight. That makes sense that the interrupter could be used to blink the hold light.

     

    John

  • in reply to Fred27

    Nice documentary.  Problem is I'll now be looking on ebay for a Strowger group selector. I'm pretty sure that it the one that moves up and down as well as rotates...  I bet thousands were scrapped in the 90's and I only want one, and then I'd obviously need to make it do something...

    Dan.

  • in reply to jw0752

    Hello John,

     

    you are right the interrupter you have shown (very nice I should say) is part of a key system where the interrupter(s) role was just to manage the blinking sequences of light related to the lines (internal and external lines) calling, on hold and so on.

     

    Below: how to connect the KSU interrupter for different lamp flashing codes

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    Below the electric connection schematics

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    Information from the following manual, provided to the technicians by the Bell systems (as you mentioned before)

    image

  • in reply to balearicdynamics

    Thanks Enrico,

     

    Great information and solution to my curiosity.

     

    John