Classic Rotary Phones Forum

Telephone Switching => Magneto & Manual (Cord Boards etc) => Topic started by: SparksNArcs on February 06, 2023, 12:35:52 AM

Title: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 12:35:52 AM
Hello everyone! I recently became a volunteer at a telephone museum, and helped another member find a new home for a switchboard he had been storing for some time.  No better way to learn about how telephone systems work than to rig some old phones up and play operator!

The unit in question is a 557A PBX (to the best of my knowledge and the prior owner's), and I spent lots of time on the threads here researching electrical connections and diagrams. This unit wound up with all 100 Secretarial lines installed, which made moving it a challenge. So far I've managed to connect my benchtop DC supply to the BATT and GND posts, and successfully connected two Station lines together; the lights on the board come on when handset is lifted, and the cord pairs light up appropriately when connections are made or taken down.

At the moment, I don't have a ringing supply, so there are some functions I can't test yet. 

However, there are a few questions I had regarding how these PBX switchboards were used originally.

1. How were Secretarial lines and Station lines used typically?
2. What triggered the Secretarial lines to light up on the board, a ringing signal?
3. What are the blank jacks without lamps on the right lower panel called/ used for?

Unfortunately I don't have any history behind where the board came from; California is what the prior owner mentioned. There are four numbered Trunk lines, and one just labeled "Welcome Wagon", which makes me really wish this thing had some documentation!
Title: Re: WE 557A PBX
Post by: G-Man on February 06, 2023, 03:26:46 AM
There is a plethora of technical information over on the TCI, but here is some info regarding of its development history: 


The images are not very detailed but I suspect that the red that is seen above the lamps are plastic dummy plugs used to visually indicate to the attendant that those particular jacks are not active. Probably the other jacks you are referring to were used for conferencing.

Interesting that the WECo No. 6 dial has an AECo number card. I suspect that this board was used in General Telephone Co. of California (GTE) territory so they installed the card. If there is a number printed on it, we can tell where is was used.

And yes, GTE often purchased and used equipment that was manufactured not only by Automatic Electric, but also by Western Electric and others.

And oh, Welcome Wagon may have been one of their clients.


Title: Re: WE 557A PBX
Post by: Contempra on February 06, 2023, 09:45:30 AM
Quote from: SparksNArcs on February 06, 2023, 12:35:52 AMHello everyone...

Welcome to this forum..SparksNArcs..the best forum specializing in vintage and old telephones..
Title: Re: WE 557A PBX
Post by: HarrySmith on February 06, 2023, 01:00:34 PM
Welcome to the forum.
Check my other post to a new member, you may want to read my warning ;D

http://www.classicrotaryphones.com/forum/index.php?topic=27181.msg262190#
Title: Re: WE 557A PBX
Post by: paul-f on February 06, 2023, 01:19:25 PM
Quote from: G-Man on February 06, 2023, 03:26:46 AMThere is a plethora of technical information over on the TCI, but here is some info regarding of its development history: 

  • https://www.telephonecollectors.info/index.php/browse/document-repository/catalogs-manuals/western-electric-bell-system/publications-and-educational-documents-by-date/blr/11542-57jan-blr-p6-answering-service-switchboards/file
A long-term search link for the BLR article is...
https://www.telephonecollectors.info/index.php/search?q=blr+answering+service+switchboard (https://www.telephonecollectors.info/index.php/search?q=blr+answering+service+switchboards)

More...
https://www.telephonecollectors.info/index.php/search?q=557+pbx
 (https://www.telephonecollectors.info/index.php/search?q=557+pbx)https://www.telephonecollectors.info/index.php/search?q=secretarial (https://www.telephonecollectors.info/index.php/search?q=secretarial)

And a Google site search in the Library will lead to many other reference documents, such as CDs and SDs, etc.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 01:57:31 PM
Quote from: G-Man on February 06, 2023, 03:26:46 AM...Interesting that the WECo No. 6 dial has an AECo number card...

The dial is actually just sitting on the desk, not hooked up at the moment. The unit previously had a touch-tone pad on the desk (associated circuitry hanging on the inside left of the cabinet), but the prior owner didn't like it and removed it in favor of the rotary; installation was not completed, however. Sadly I don't have the correct bracket to attach it to the desk, although all of the screws are present for that.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 02:08:57 PM
Quote from: paul-f on February 06, 2023, 01:19:25 PMA long-term search link for the BLR article is...
https://www.telephonecollectors.info/index.php/search?q=blr+answering+service+switchboard (https://www.telephonecollectors.info/index.php/search?q=blr+answering+service+switchboards)

More...
https://www.telephonecollectors.info/index.php/search?q=557+pbx
 (https://www.telephonecollectors.info/index.php/search?q=557+pbx)https://www.telephonecollectors.info/index.php/search?q=secretarial (https://www.telephonecollectors.info/index.php/search?q=secretarial)

And a Google site search in the Library will lead to many other reference documents, such as CDs and SDs, etc.

Just looked at the first document regarding the 557A & B, which I had read before, but apparently not close enough! I'm a little young to remember when people didn't just have answering machines, so the concept of an answering service was a bit foreign. That did clear up a few things, though.

Based on that information, this is what I understand about the operation:
1. Central Office redirects calls on off hours from businesses to Answering Bureau, which lights up corresponding lamp on Secretarial panel.
2. Secretarial lines can be answered by the attendant for taking messages, or routed to a Station line to speak with a manager or other employee at the Bureau.
3. Station lines can call out on Trunk lines or to other Station lines, but calls cannot go out through Secretarial lines, and Secretarial lines cannot be connected to Trunk lines. 

My next question is, once the attendant had written down messages for various businesses, did they tie into a trunk line a dial out to each business to give them their messages the next day?
Title: Re: WE 557A PBX
Post by: HarrySmith on February 06, 2023, 02:49:58 PM
I have a couple of switchboard dial mounts that I got in a box of parts. I would be happy to donate one as I have no use for them. I cannot tell from the pictures what it looks like.  Does anyone have a picture of the dial mount? If not I can post pictures of what I have in the next few days, after I dig them out, to see if they will work.
Title: Re: WE 557A PBX
Post by: G-Man on February 06, 2023, 02:59:54 PM
Quote from: SparksNArcs on February 06, 2023, 02:08:57 PMMy next question is, once the attendant had written down messages for various businesses, did they tie into a trunk line a dial out to each business to give them their messages the next day?
Typically the business would call-in to check for messages, i.e.- "Bessie, did anyone call while I was away" or "did anyone call while I was returning from the restaurant?"

Or if they were on duty, such as a doctor, veterinarian, plumber, or 24-hour diesel truck repair service, the answering service attendant would call the restaurant (or other location that they were previously informed of by the customer), where they were dinning at.

 They would also screen calls so the subscriber would not have to provide their private number and be bothered by annoying or frivolous calls at home, so the attendant would call only if it were urgent.

Also, the secretarial lines only respond to ringing current by means of a cold-cathode tube, so the attendant cannot simply plug into an idle line place outgoing calls or on a busy line to snoop on conversations.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 03:11:12 PM
Quote from: HarrySmith on February 06, 2023, 02:49:58 PMI have a couple of switchboard dial mounts that I got in a box of parts. I would be happy to donate one as I have no use for them. I cannot tell from the pictures what it looks like.  Does anyone have a picture of the dial mount? If not I can post pictures of what I have in the next few days, after I dig them out, to see if they will work.

I would appreciate that! I'll get a better picture of the mounting location and the dial assembly later today. The desk has two threaded inserts one above the other, maybe 2" apart. The bracket is, I think, a U-shaped piece that the dial "clips" onto and secures with a screw or two.
Title: Re: WE 557A PBX
Post by: G-Man on February 06, 2023, 03:22:22 PM
It would have originally been equipped with a rotary dial but had since been retrofitted with a DTMF dial.

I have included a jpeg showing the 25B-mounting bracket that would be needed to mount the 34D-adapter to the writing shelf.
Title: Re: WE 557A PBX
Post by: G-Man on February 06, 2023, 03:34:56 PM
Also, where are you located? If you are close enough I probably have a ringing supply that I would be willing to donate. Otherwise, the cost of shipping would probably be prohibitive.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 03:52:37 PM
Quote from: G-Man on February 06, 2023, 03:34:56 PMAlso, where are you located? If you are close enough I probably have a ringing supply that I would be willing to donate. Otherwise, the cost of shipping would probably be prohibitive.

I am in Auburn, WA. I've started volunteering at the Connections Museum in Georgetown.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 03:54:34 PM
Quote from: G-Man on February 06, 2023, 03:22:22 PMIt would have originally been equipped with a rotary dial but had since been retrofitted with a DTMF dial.

I have included a jpeg showing the 25B-mounting bracket that would be needed to mount the 34D-adapter to the writing shelf.

That's what I was thinking of! The dial still has the fingers on the bottom to engage with the terminal board on the bracket, although they are a little bent.
Title: Re: WE 557A PBX
Post by: G-Man on February 06, 2023, 04:07:56 PM
Quote from: SparksNArcs on February 06, 2023, 03:52:37 PMI am in Auburn, WA. I've started volunteering at the Connections Museum in Georgetown.
I suspect that Sarah and the crew at the Connections Museum would have extensive documentation and needed components including power supplies and dial brackets at their fingertips, etc., but perhaps not. Otherwise it would save you the cost of today's expensive shipping.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 04:55:00 PM
Quote from: G-Man on February 06, 2023, 04:07:56 PMI suspect that Sarah and the crew at the Connections Museum would have extensive documentation and needed components including power supplies and dial brackets at their fingertips, etc., but perhaps not. Otherwise it would save you the cost of today's expensive shipping.

I imagine they do, but as I'm a relatively new member and still need to prove my worth; I didn't want to start asking for things for my personal collection. There are cheap solid state ringing module options on Ebay, so I may get one of those. I'll ask the volunteers if they have any spare equipment for sale the next time I'm there.
Title: Re: WE 557A PBX
Post by: HarrySmith on February 06, 2023, 05:10:19 PM
IIRC that looks like what I have. I will dig them out in the next couple of days to check. If it is the correct one just pay postage and it is yours.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 06, 2023, 05:58:45 PM
Quote from: HarrySmith on February 06, 2023, 05:10:19 PMIIRC that looks like what I have. I will dig them out in the next couple of days to check. If it is the correct one just pay postage and it is yours.

You are a scholar and a gentleman, thank you!
Title: Re: WE 557A PBX
Post by: HarrySmith on February 08, 2023, 07:23:00 PM
OK. I found it! There is 2 other parts that I think might go with it. I am not sure. See pictures. Somone will know what they are.
Title: Re: WE 557A PBX
Post by: G-Man on February 08, 2023, 07:54:30 PM
Quote from: HarrySmith on February 08, 2023, 07:23:00 PM
OK. I found it! There is 2 other parts that I think might go with it. I am not sure. See pictures. Somone will know what they are.
Harry-

He hasn't posted a detailed photo of his but I believe he already has all of the parts that are shown in your photo with the exception of the 25-type mounting bracket that is shown in the jpeg that I posted earlier in this thread and is shown in a red rectangle .

Also, there is a  threaded pin that retains the dial cup to the bracket but I suspect that it may not be in your stash. ISTR that it was made of stainless steel and may remind some of a headless screw.

If I can remember, I will take a photo of one of my switchboards and post it here. If you are unable to locate one, then he can make do with a similar size of steel rod.
Title: Re: WE 557A PBX
Post by: G-Man on February 08, 2023, 08:11:24 PM
Here is another jpeg that shows the bracket within a red rectangle.

I also drew a blue line through the dial cup to show the location of where the headless retaining screw goes.
Title: Re: WE 557A PBX
Post by: HarrySmith on February 08, 2023, 08:51:08 PM
OK. I misundestood. I thought all he had was the dial and needed the mount. I do not have that other part, only what is pictured. Sorry!
Title: Re: WE 557A PBX
Post by: G-Man on February 09, 2023, 04:07:24 AM
Quote from: HarrySmith on February 08, 2023, 08:51:08 PMOK. I misundestood. I thought all he had was the dial and needed the mount. I do not have that other part, only what is pictured. Sorry!
Harry-

You stepped up to the plate as you usually do to help a fellow collector in need, so there is no need to be sorry!

Thank you again for setting a sterling example of selflessness for the rest of us to follow!
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 09, 2023, 02:19:06 PM
It totally slipped my mind to get another photo of the dial assembly; will do that after work. Thanks for digging through your stash for me!
Title: Re: WE 557A PBX
Post by: HarrySmith on February 09, 2023, 02:40:00 PM
YW.
It does not look like it would be difficult to make something to replace that bracket. Other than the electrical connections which can probable be bypassed with some longer wires.
Just thinking out loud ;D
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 09, 2023, 03:59:19 PM
Quote from: HarrySmith on February 09, 2023, 02:40:00 PMYW.
It does not look like it would be difficult to make something to replace that bracket. Other than the electrical connections which can probable be bypassed with some longer wires.
Just thinking out loud ;D

I work in a machine shop, so I'd better be able to come up with something, or my boss'll be disappointed in me! The dial also has a set of wires coming out of the bottom, seemingly to bypass the contacts.
Title: Re: WE 557A PBX
Post by: HarrySmith on February 09, 2023, 04:12:01 PM
From what I saw on the parts I pulled out the dial connects to the terminals on one side of the mount and apparently the other side of the mount connects to the bracket.
Title: Re: WE 557A PBX
Post by: SparksNArcs on February 09, 2023, 10:50:14 PM
For future reference, here are the mounting points for a dial on the 557A, and presumably most other WECo PBXs. The right two screws are hiding threaded inserts in the desktop, and the left screw is just a hole plug; the wiring passes through this hole.

Also included a picture of my dial base, which I need to pop open, as it seems to have the contacts on the bottom bypassed with a length of cable.
Title: Re: WE 557A PBX
Post by: HarrySmith on February 10, 2023, 07:42:06 AM
Thanks for the pics. I guess those wires are what I mentioned to bypass the connections on the bracket.
Title: Re: WE 557A PBX
Post by: G-Man on February 11, 2023, 12:23:53 PM
Quote from: SparksNArcs on February 09, 2023, 03:59:19 PMI work in a machine shop, so I'd better be able to come up with something, or my boss'll be disappointed in me! The dial also has a set of wires coming out of the bottom, seemingly to bypass the contacts.
Yesterday I went out to one of my storage areas and took photos of a 25-type mounting bracket that is installed on a WECo toll-testboard.

Aside from being very dusty, it should provide you with a better perspective if you decide to fabricate one yourself.

I also looked for loose dial mounts and brackets but wasn't successful (I know they're somewhere), however I did find a pleasant surprise when I came across about a half-dozen coin collectors that I had forgotten about long ago!