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Toll Switchboard

Started by JerryP, September 10, 2013, 07:20:48 PM

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Any ideas on how to build a "cord circuit"?  What kind of equipment would I need to get one working?


I think I can build one if I can find two repeating coils.  Any one know where I can find a WE 20A and a WE 20C or equivalent?


Try Steve Hilsz, email If he does not have them he can probably point you in the right direction.
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"


I tried that.  No luck!  Any other ideas?


Hi I have some AE 1200K.
I think that they are a 1 to 1 coil.
They are used in trunks. They have 8 post. Double windings.
they can be used as  battery feed on both sides of the coils if other relays are used with them for supervision. I also have some of the relays.



The AECo 1200K should be a good choice for a cord circuit. I believe it is an equivalent of a WECo 120K.

Here are a few wiring diagrams of cord circuits using repeating  coils.


Thanks to both of you for that.  Weco355aman, would you email me at so we can work something out on the coils and relays.  Again, THANK YOU both for the help.


The ( F ) Fig is what i had in mind. I do have the relays need to make fig (f).
This will provide Talking battery for both sides. If you plan on trunk calls you
only nee a B F feed on one side of the cord.   Use fig ( C ) for trunk side connections.  You will need a relay connected to the ring key to swing the station (called phone) from the repeat coil to ringing generator. (floating not connected to ground) unless you really know what your doing.


Here is some photos of a working 3CL toll switchboard.  When completed it will have approximately
40 trunks, this will include toll stations, Dial 0 from 6 differant switching systems and 6+ Asterisk
outbound trunks to Cent/PSTN.