Author Topic: Rural multi-line telephone company central office frequency ringer test/check box  (Read 192 times)

Offline TaylorStreet

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Here's what I was told by the fellow from whom I bought it:  This multi-line box was removed from a rural telephone office back in the day and was used to handle party lines.

Here's what I know for sure:  squat.

There are no markings as to manufacturer or part number other than "72-A" on the ?condensers?

This is part of a private collection I purchased that was more like an accumulation, since the person just took home 'interesting' things the technicians used to bring back to the warehouse in which he worked.  He didn't do any renovation or investigation except what was necessary to mount them on his den wall.  My own expertise with telephones is minimal.

I would appreciate any holes in my knowledge base being filled about this item.

Online TelePlay

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Interesting artifact of times gone by.

With all of them being frequency ringers, only one would ring at a time but for what purpose? All the gongs look the same so they would each sound the same, unless the cadence were different for each line.

            John . . .

              

unbeldi

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My first "guess" is that this equipment was made by the Kellogg Switchboard & Supply Company.
Kellogg was one of the first, if not THE first company that made five-frequency ringing equipment for central offices, five-frequency pole-changers, etc.
They advertised their new five-frequency system extensively and became the leader in frequency-selective signaling.

The screw locks for the front door also look like Kellogg parts.

The five-frequency harmonic system used the standard frequencies  of  (1) 33 1/3 Hz, (2) 50 Hz, (3) 66 2/3 Hz and (4) 16 2/3 Hz.
The first three are the 2-times, 3x, and 4-x harmonics of the base frequency 16 2/3 Hz, which was the last one installed in sequence.
Later an additional frequency was added, 25 Hz, which is the 1.5-times multiple.

« Last Edit: August 09, 2017, 05:28:25 PM by unbeldi »

Offline poplar1

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It may have been used inside the central office building to verify that each of the 5 frequencies used on party lines was accurate.

According to Roger Conklin, even a small deviation from the precise frequency would keep a frequency selective ringer from ringing.
"C'est pas une restauration, c'est une rénovation."--François Martin.

unbeldi

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Ok, so I see the following numbers on the ringers:  72-A and 101A.   These are indeed Kellogg part numbers of the 1920s and 1930s.

72-A:
  500 Ω DC resistance for the 33 1/3, 50, and 66 2/3 Hz ringers
  2500 Ω DC resistance for the 16 2/3 Hz ringer

101-A: 2500 Ω DC resistance for the 25 Hz ringer


I believe this is the Pole-Changer Test Set, as shown in Catalog No. 9, only for a different set of frequencies:



« Last Edit: August 09, 2017, 05:44:27 PM by unbeldi »

unbeldi

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Also from the same catalog comes this table of ringers in your box:


Offline TaylorStreet

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Geez.... what took youse guys so long?  ;D

Seriously, thanks for all the information.  Now all I have to do is hook up with someone who is trying to replicate a rural telephone company's office....  There's gotta be a million or two of them.

Alex G. Bell

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I believe this is the Pole-Changer Test Set, as shown in Catalog No. 9, only for a different set of frequencies:
Little doubt about it.  I have a set of four different WE wooden box frequency ringers (43-type?  127-type?) I got from someone who salvaged them from a rural CO where, he said, they were used for testing the ringing plant.

Offline Jon Kolger

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When I worked for GTE in Indiana, I worked in rural areas and in a number of smaller, rural central offices.  Most of them were step-by step, even as recently as 1996 (when I moved to Texas) .  Each CO had a ringer box similar to this mounted on the frame, so that ring frequency could be tested.  All you had to do was connect the test leads to your line, call it, and the ringer corresponding to the correct ring frequency would ring.  It could also be used to test to see if the ring generator was putting out the correct frequency, although the CO techs had much more accurate equipment to make those types of tests.  Many of the remote COs were unmanned, so we outside guys had to do a lot of the CO work ourselves.