Intercom Systems - Information

Discussion in 'Layout Electronics' started by klrwhizkid, Jan 11, 2010.

  1. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    I thought I'd start another thread here in the Electronics Section.

    Anyone with expertise, diagrams, sources, reference materials please weigh in here.

    I will start by posting some of the parts, information and diagrams that I have, but they are offered as thought starters since I have not become a subject matter expert, yet.

    The Atlas CE-2A-PT beige handset station is an example of the ones I intend to use out on the layout. Atlas also made/makes the WE-2A which has a slightly different hook. The EST 6830-6A Remote Handset red station will be for the dispatcher.
    The power unit pictured below is a Western Electric SD-81824-01.

    Attached Files:

    Last edited by a moderator: Jan 12, 2010
  2. bob_wintle

    bob_wintle Member Supporter

    Where does one get this kind of stuff?
    El Bob Oh
  3. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    Some of the stuff I salvaged years ago (pwr supply, most of the intercom paging system handsets) from the Kroger store I was working at when they decided to remodel the entire store. I have picked up some recently off ebay (although it took a lot of searching between search terms; vintage telephone, remote, paging, handset, intercom).
    There are some communications guys out there in the greater model railroading community (I know they exist; have heard them being talked about, just don't know/remember names - one takes care of the Bella Vista group, another here locally in KC).
  4. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    Sixty views thus far, but no additional input - if you have a contact that can help us sort out the wiring of an intercom system based on old phone handsets, get their permission and contact info for me to contact them (PM me with their contact info). I offer to be the clearing house/respository of information or we can get them registered and they can contribute directly.
  5. Sirfoldalot

    Sirfoldalot Supporter Supporter

    Keith .. wish I could help - sigh.
    When it warms up there again (if ever), find an older guy working for the local phone people. He would probably be glad to help you with a drawing, or, maybe even hands on.
  6. pbender

    pbender Member Supporter

    I have a genuine Frisco cab radio phone handset. Any thoughts on how one would wire that into this kind of a system?

    The layout I've been operating on recently just has all the phones wired as party line phones. You pick up the handset, and everyone can hear your conversations with the dispatcher

    Last edited by a moderator: Jan 12, 2010
  7. TAG1014

    TAG1014 Supporter Supporter

    I guess using "party line" phones would be something like today's radio dispatching.

  8. friscomike

    friscomike Administrator Staff Member Administrator Supporter


    The Texas Western purchased a PBX with eight extensions. The PBX allows direct dialing to another station. We're in the process of collecting hand sets now that can connect to the switch. Finding the old handsets (nondigital) at a reasonable price has been tough. The PBX was a [FONT=&quot]SOHO-PBX SP-208C (2 Phone Lines x 8 Extensions PABX).[/FONT]

    Our objective was to have one phone at the dispatcher's office and the others at the "phone booths" at stations and yards like the prototype railroads did.

    I liked the idea better than radios and since we operate in the 1945-1959 era.

    Good luck with your quest,
  9. Rick McClellan

    Rick McClellan 2009 Engineer of the Year


    The local KC telephone guru is Fred Haines of KCK. As far as I know, he is no relation to the Haines sisters from White Christmas although he does bear a striking resemblence to Santa Claus. :D

    Fred is a former SW Bell Telephone technician and now is retired. His house is a telecom museum. My favorite phone is an old solid oak wind up type phone like you saw at Sam Drucker's store on Petticoat Junction. :eek:(Those under 30 will not know what I am talking about.)

    He has salvaged a lot of telephone "networks" I believe he calls them and 10v power supplies over the years. What Fred does is supply the networks (one needed for each handset station), the power supply and a diagram to show you how to hook it all up. You supply the handsets, cradles, wire and the house to put it in. I used CAT 5 cable to install my network but I ran out of wires at Tulsa staging so I will need to run another CAT 5 as I push further south on the layout.

    The phones work pretty good as you can attest, especially if the callers speak directly into the mouth piece.

    I think I got out of Freds for about $200 including the power supply and about 10 networks. :eek: That may seem steep but I sure didn't want to scrounge up all that stuff myself.

    I could probably dig up my diagram that Fred drew for me on a paper grocery bag.
  10. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    I am happy to report that I am making some progress in this endeavor through perseverence. I am in the process of designing a system based on what I am learning and then will pass it the circuit diagram by a local expert, then test it without waiting to build the layout. I hope to have results before too long. When I have a compendium of the garnered knowlege, I will post all the bits and pieces.
  11. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    Here are two simple intercom diagrams.
    One is just a "party line" where anyone that picks up a handset can talk and hear.
    The other is still a party line but with buzzers added so remote stations can call the dispatcher and individual buzzers at each station so the dispatcher can call individual stations.

    The handsets are old Western Electric telephone handsets with carbon microphones and receivers. These can be found on ebay from time to time for reasonable prices.

    Hook switches will allow more handsets to be connected without significant performance drop off. Beyond some point (number of handsets) the system would require a different configuration involving networks (transformers) at each station. (I'm still investigating that solution - more to follow).

    Attached Files:

    Last edited by a moderator: Apr 19, 2010
  12. Sirfoldalot

    Sirfoldalot Supporter Supporter

    Very nice drawings - Keith - Thanks for the info. :)
  13. klrwhizkid

    klrwhizkid Administrator Staff Member Administrator Supporter

    Here are some designs that incorporate what the telecom guys call networks (transformers plus some other stuff inside). Networks can allow a system to be very simple, using only two wires to interconnect stations and create a party-line system.

    The designs on this post include a lamp at the dispatcher's station for every station on the layout and a buzzer at every station. If someone out on the layout picks up a handset, then the corresponding lamp at the dispatcher's station will illuminate. The remote station also has a pushbutton to buzz the dispatcher if the lamp doesn't get his attention. The dispatcher can also select one of the remote stations with the selector switch and pushbutton and buzz that station to get their attention.

    Two good sources for telephone parts, handsets and handset hangers with "2 Form C switches" are:
    Mike Sandman at and
    Ron Knappen at

    For pushbuttons, I have used the simple, round doorbell buttons, but they are starting to get hard to find cheap because everyone wants fancy doorbell buttons.
    For the indicator lamps, I would recommend 12 volt LED indicators - they use little current, so they won't stress a power supply.

    If you are serious about building your own system, send me a PM - I will be glad to discuss in more detail.

    Attached Files:

    Last edited by a moderator: May 20, 2010

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