Author Topic: Western Electric Switchboard Question  (Read 436 times)

Offline Fabius

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Western Electric Switchboard Question
« on: May 02, 2017, 07:26:01 PM »
As the search for a switchboard goes on I see this one on ebay. It's the first I;ve seen with black equipment and a different connect panel rather the a wire block. Still a 551? Thanks.
Tom Vaughn
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Alex G. Bell

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Re: Western Electric Switchboard Question
« Reply #1 on: May 17, 2017, 09:39:53 PM »
Maybe not.  Early Panel & SXS office equipment were painted black.  Must have been extremely dismal to work in them!

(Thinking out loud): It looks like a 551B front and back but a 554 was an answering service swbd based on the 551.  Note that this has separate 200-series jacks mounted on strips (thick sleeves visible) rather than the thinner "strip mounted jacks".  TAS swbds used separately mtd jacks because the auxiliary contacts required on a jack associated with a customer's line on a TAS swbd (rather than a PBX EXT) exceeds the complexity available on strip mounted jacks.  Earlier 550s also used separately mounted jacks.

A TAS swbd responds to ringing on a customer line rather than DC continuity on the loop and has provisions to prevent the operator from entering a line except when ringing to prevent eavesdropping, requiring a relay per customer line for both purposes.  In a 554 these are normally mounted on the top part of the gate where the screw terminal board is on this one.  554s also had larger designation strips associated with the jacks to provide ample space to write in a long "answering phrase" for each jack for the operator to know what to say when answering. 

My conclusion is that it's "just" a very early 551B from before strip mounted jacks were introduced to accomplish the eventual 160/320 extension capacity using 10/20-jack strip mounted jacks.  It's an early example and probably one of few like it still left. 
« Last Edit: May 17, 2017, 10:17:32 PM by Alex G. Bell »

Offline Fabius

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Re: Western Electric Switchboard Question
« Reply #2 on: May 17, 2017, 10:41:11 PM »
Thanks for the info. I notice that this board has the hole (capped) for a hanging transmitter. An indication of an earlier board.
Tom Vaughn
La Porte, Indiana
ATCA Past President
ATCA #765
C*NET 1+ 821-9905

Alex G. Bell

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Re: Western Electric Switchboard Question
« Reply #3 on: May 17, 2017, 10:47:14 PM »
YW.  Yup! 

I have a 1930 vintage 551BX, which is a special made for use with a 1928 vintage (IIRC) dial 740A (the combination is 740AX) before the 552 was introduced in 1932 for that purpose.  It has the boom still in place.  It also has the earlier brass dial mounting with 20 angle to the keyshelf instead of the steeper bakelite 37 ones and has a #2 dial.

I had not thought about that when answering your original question and frankly it's been "back to the wall" so long I don't remember whether it's black or silver inside.  My conventional 1941 551B is silver and my 552 is gray and has 70-type cartridge fuses instead of 35-type "grasshoppers".