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In Memoriam: How to use a rotary dial telephone

Jerome Marot

Well-known member
The following video was presented in 1927 to California residents who went down to the local cinema to learn how to use the dial telephones. Although it is not related to photography, I cant resist presenting it here in the hope it will be enjoyed by some of our most respected members. I think that one of them worked in that particular field of technology.

https://www.youtube.com/watch?v=WmqHe7uG0dE

Members who never worked in that particular field of technology may wonder how automatic dialling worked before computers and solid state electronics. That video shows the wonders of what happened when you operated the dial:
https://www.youtube.com/watch?v=xZePwin92cI

That one showed who it was done manually, before dial telephones:
https://www.youtube.com/watch?v=xJ1fKFqt7qU


Actually, AT&T has a whole archive of such videos here: http://techchannel.att.com/showpage.cfm?ATT-Archives, but it requires the now obsolete flash plugin.
 

Doug Kerr

Well-known member
Hi, Jerome,

Very nice. Thank you. I had not seen those before.

The following video was presented in 1927 to California residents who went down to the local cinema to learn how to use the dial telephones. Although it is not related to photography, I cant resist presenting it here in the hope it will be enjoyed by some of our most respected members. I think that one of them worked in that particular field of technology.

https://www.youtube.com/watch?v=WmqHe7uG0dE
Very nice. Cute subscriber. I note that her 51AL desk stand telephone is apparently in a decorator color!

I especially like the frantic scene at what is now called the directory assistance desk (formerly "information").

Of course we see everything here speeded up as that film was certainly shot at 16 fr/s and we see it here either at 24 fr/s or even 30 fr/s.

I do like the score added by the transcriber!

Members who never worked in that particular field of technology may wonder how automatic dialling worked before computers and solid state electronics. That video shows the wonders of what happened when you operated the dial:
https://www.youtube.com/watch?v=xZePwin92cI
Very nice treatise on the step-by-step system (known outside the Bell Telephone System as the Strowger system).

Interesting to see that the equipment in the central office is fairly old. We see that when the technician first takes the cover off a switch and works with it. We see from the closeup that it has the flat coil spring (like a clock spring), in a little brass cup, rather than the newer helical coil spring, atop the shaft.

But in that lovely little demo system, we see the newer type of spring.

That one showed who it was done manually, before dial telephones:
https://www.youtube.com/watch?v=xJ1fKFqt7qU
Nice review of the history of manual switching, and a nice discussion of some of the details. Wonderful to see the gesture used to make the busy test with the cord circuit plug and then the special gesture used to actually insert the plug in that jack (that gesture assures that the pull of the cord, which runs out of sight through a weighted pulley to take up any slack, does not disrupt the insertion).

Actually, AT&T has a whole archive of such videos here: http://techchannel.att.com/showpage.cfm?ATT-Archives, but it requires the now obsolete flash plugin.
Nice. Thanks.

As a matter of fact, my extensive articles on many of these matters are now being updated and "improved". As soon as this is done I will post links to them. (The existing issues are fine, but . . .

The matter of the introduction of dial service is a very complex one. There is of course the matter of arranging things technically to facilitate the subscribers' embrace of the new modality. Then there is the "education" of the subscribers, as done in your first video.

Of course, in a large city, with numerous central offices, it was impractical to "flash cut" all of them to dial service at once. The conversion had to be progressive, and might span a decade. Thus there is the very complex matter of the inter operation of the new "dial", central offices with the existing "manual" central offices. As always, there are both technical and "human factors" issue intertwined here. This is in fact the topic of a new article I am about to publish.

Thanks again for bringing us these jewels of insight into what I have often called "the greatest story ever told" (no apologies to Christian bible scholars).

Best regards,

Doug
 

Jerome Marot

Well-known member
Of course we see everything here speeded up as that film was certainly shot at 16 fr/s and we see it here either at 24 fr/s or even 30 fr/s.
I don't think so. The video is shown at 30 fr/s (29.97, actually), but shows artefacts characteristic of the insertion of intermediate frames. Watch the part around 3:00 frame by frame, for example.
 

Doug Kerr

Well-known member
Hi, Jerome,

I don't think so. The video is shown at 30 fr/s (29.97, actually), but shows artefacts characteristic of the insertion of intermediate frames. Watch the part around 3:00 frame by frame, for example.
The dial (likely a 2A) in that desk stand telephone set almost certainly operated at a nominal speed of 10 pulses/second, whereas in the video the dial finger wheel returns much faster than consistent with that. I've lost the ability to determine its actual speed "by eye" very precisely, but I suspect it is seen at about twice actual speed.

I can do some forensics later today to see just what the discrepancy is.

It may be that the original film (at 16 fr/s) was "taken in" as if it at 24 fr/sec, and then was converted (from that assumed speed), with "3-2 pulldown" to 29.97 fr/sec for the video (there being a further 0.1% speed discrepancy introduced by that process).

Perhaps the situation is different for different clips within the entire video.

In any case, the directory assistance operators were operating (!) at a comically frantic pace.

It is interesting that in some of the earliest dials (the 1 type), in the center of the finger plate, rather than there being the familiar removable frame holding a paper card with the telephone station's number on it, there was a domed metal plate carrying concise operations for working the dial. The number card was then in a frame (128A card holder) just above the transmitter mouthpiece.

In a later practice, where the paper card in the center of the dial was in use in was use, the preprinted number card blanks had, above the rounded-corner rectangle that was to carry the number, the phrase "Please wait for dial tone".

Best regards,

Doug
 

Doug Kerr

Well-known member
Hi, Jerome,

Here we see the instruction plate I spoke of:



Here we see the number card in the 128A card holder:



There is a wonderful story that deals with how the number cards were set up for this use but I won't trouble you with it right now.

This card blank was in a way set up for use with the 128A card holder but in a way wasn't (that's part of the story), and it has the "please wait for dial tone" on, it, but of course it can't be read in this situation.

Best regards,

Doug
 

Maggie Terlecki

Active member
Merci, Jerome for this. It was not at all what I expected, especially the first one with the music and how long and detailed the video shows people how to dial. In the second one, I was surprised at how much equipment was needed to be make it capable of calling someone without a switchboard. Holy cow! And in the third, I think I was taken aback by how late switchboards existed. I had no idea that in the 70s, 80s etc., these were still in operation. Was cool to watch and see the evolution of something we take for granted.
Thanks for the share; Maggie :)
 

Peter Dexter

Well-known member
That was fun. Thanks. I wonder when the last dial phones were produced. Some time in the 80s? When my father lived in Galion, Ohio he had an Ericofon produced there by North Electric.
 

Jerome Marot

Well-known member
Hi, Jerome,
The dial (likely a 2A) in that desk stand telephone set almost certainly operated at a nominal speed of 10 pulses/second, whereas in the video the dial finger wheel returns much faster than consistent with that. I've lost the ability to determine its actual speed "by eye" very precisely, but I suspect it is seen at about twice actual speed.

I can do some forensics later today to see just what the discrepancy is.
I can do that for you.

At 3:00 in the movie, the number 6 is dialled. Return time is 18 pictures, so 0.6s. The dial is of the sort where 0 gives a full return, therefore 10 pulses and you said these would be 1s. Number 6 would then be 0,6s which is consistent with the movie.
 

Doug Kerr

Well-known member
Hi, Jerome.

I can do that for you.

At 3:00 in the movie, the number 6 is dialled. Return time is 18 pictures, so 0.6s. The dial is of the sort where 0 gives a full return, therefore 10 pulses and you said these would be 1s. Number 6 would then be 0,6s which is consistent with the movie.
Thank you so much. Yes, that seems consistent I have no idea why it seemed wrong to me.

I'm tangled up in another catastrophe just now, but later I will try and see what messed me up.

Thanks again.

Best regards,

Doug
 

Jerome Marot

Well-known member
I wish that the other catastrophe untangles soon. FWIW, I thought that the dial returned too fast as well. Probably our memories are simply not to be trusted.
 

Jerome Marot

Well-known member
Merci, Jerome for this. It was not at all what I expected, especially the first one with the music and how long and detailed the video shows people how to dial. In the second one, I was surprised at how much equipment was needed to be make it capable of calling someone without a switchboard. Holy cow! And in the third, I think I was taken aback by how late switchboards existed. I had no idea that in the 70s, 80s etc., these were still in operation. Was cool to watch and see the evolution of something we take for granted.
Thanks for the share; Maggie :)
Il n'y a pas de quoi, Maggie. I enjoyed the videos just as much.
 

Doug Kerr

Well-known member
Hi, Jerome,

Yes, I see that the dial return when dialing "6" seems to take 18 frames, although there is no motion in about 2 of them.

And upon looking at the scene again, I think I was somehow misled (two many moving "shadows" and such), and that indeed this is very close to 10 pulses/sec.

Best regards,

Doug
 

Doug Kerr

Well-known member
Hi, Jerome,

I wish that the other catastrophe untangles soon.
It did.

FWIW, I thought that the dial returned too fast as well. Probably our memories are simply not to be trusted.
Yes (as I commented in another post, not having seen yours) I think some "optical illusions" have been at work on us.

There was a time when, hearing a radioteletypewriter signal, I could tell ("by ear") the difference between 45.45 and 50 baud operation (it was of course the character rate, not the modulation rate itself, to which I was sensitive). But I suspect no more!

Thanks again.

Best regards,

Doug
 

Doug Kerr

Well-known member
Hi, Maggie,

Merci, Jerome for this. It was not at all what I expected, especially the first one with the music and how long and detailed the video shows people how to dial. In the second one, I was surprised at how much equipment was needed to be make it capable of calling someone without a switchboard. Holy cow!
Although that little video is very nice, and very illuminating, and in fact rather technically accurate, it only shows the tip of the iceberg. The overall complexity of a single switch, and a single central office, and then of a whole network in a major city, is just breathtaking.

And in the third, I think I was taken aback by how late switchboards existed. I had no idea that in the 70s, 80s etc., these were still in operation.
Yes, although by then they were few and far between.

The last Bell System manual switchboard in the state of New Jersey was decommissioned in about 1963. I had the honor of attending its dismantlement.

Was cool to watch and see the evolution of something we take for granted.
Indeed. "The greatest story ever told."

Best regards,

Doug
 

Doug Kerr

Well-known member
Hi, Peter,

That was fun. Thanks. I wonder when the last dial phones were produced. Some time in the 80s? When my father lived in Galion, Ohio he had an Ericofon produced there by North Electric.
Yes, Galion was in fact the home to North Electric for most of its life (although it had started someplace else in Ohio.

The Ericofon was of course an L.M. Ericsson design, and I think North Electric made them under license. (North Electric was for a while partly owned by Ericsson.)

I'm not sure when phones with rotary pulse dials stopped being made in any substantial quantity.

Best regards,

Doug
 

Maggie Terlecki

Active member
Hi, Maggie,



Although that little video is very nice, and very illuminating, and in fact rather technically accurate, it only shows the tip of the iceberg. The overall complexity of a single switch, and a single central office, and then of a whole network in a major city, is just breathtaking.



Yes, although by then they were few and far between.

The last Bell System manual switchboard in the state of New Jersey was decommissioned in about 1963. I had the honor of attending its dismantlement.



Indeed. "The greatest story ever told."

Best regards,

Doug
Thank you, Doug, for this further information. Indeed, it was marvelous to watch!
 

Doug Kerr

Well-known member
As you can well imagine, I have a substantial collection of photographs of manual telephone switchboards, of many types, in many places, over many years.

One of my favorites is this (for which I don't have any reliable information about time or place, but the the time was likely very early in the 20th century).


This board had 50 positions (operators' "work stations"), not all of which would be staffed except during the busiest traffic times of day. The board as we see it is equipped to handle up to 7700 lines.

For each line, there were a number of jacks (all connected in parallel), spaced in this case at a pitch of 3 positions.Thus any operator could always reach a jack for the called line, but it might be in front of the position to the right or the left, so a "boarding house reach" was a needed skill of an operator. In later designs, the needed reach was reduced a bit.

This was called (not surprisingly) the "multiple jack" scheme. The whole array was in fact called the "line multiple". In this case, it comprised about 123,000 jacks, tied together by about 23,000 conductors (3 per line) running the whole length of the switchboard, with about 370,000 soldered connections.

The whole multiple was constructed at the factory, and you can imagine the job it was to pack it (folded up) and transport it.

This certainly seems to be a "staged shot".

Best regards,

Doug
 
Does anyone else recall being able to dial a phone which had its dial locked by simply pulsing the receiver cradle the appropriate number of times for each number. I graduated from high school in 1959 (in Delaware) and could do it, so we had those phones then and probably for about ten years more.
 
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