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Identification of Ringer found in 1955 500 set

Started by zapper, November 20, 2013, 11:15:10 PM

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dsk

Tuned ringers, harmonic ringers, frequency ringers, party line ringers, seems for me to be names on the same thing, depending on telco and background.

Here in Norway this is completely unknown, and I am sure it is just made as an IQ test to see if the Europeans might follow, and understand. ;D

If i understand this right different electric frequencies was used to call different subscribers on a common line. By making the "ringer capacitor" circuit frequency selective, like the fingers moving in an old frequency meter this was working OK.

To tune a frequency ringer to another frequency you have to change capacitor value, weight of the clapper, and the stiffness of the spring acting as hings for the clapper. This is not easy to do.

dsk

Phonesrfun

#16
dsk:

All of that is correct, but I might add one or two things.  Frequency and harmonic ringers are the same thing, and yes they were made with physical properties as well as electrical (coil inductance and the value of the capacitor) to make them highly selective.

However, there were other ways to selectively ring parties on a common telephone line.

The Bell system did not use frequency/harmonic ringing much.  It is my understanding that they only used it in old central offices where they had purchased a group of subscribers and the accompanying central office from an independant phone company.  Most of these were rural and most were party line arrangements.

Rather than frequency selective ringing, Ma Bell was more into divided and coded ringing, where standard ringers could be used.  One such arrangement was such that three subscribers on a line could each get ringing without others on the line being rung.  THis was divided ringing.  One party would have ringing bridged across the line, and the other two had ringing between one or the other side of the line and ground.  You could have more parties by using a combination of this and coded ringing, I.E. long-short, short-short, long-long, etc.

Still another way to selectivly ring more than three parties on a line without doubling up with coded ringing was to use the cold cathode tube in series with the ringer and capacitor.  In this case the tube could be biased negatively or positively with line voltage, and then by using the combination of the bias along with divided ringing, the possibilities grew to I think 8 without using coded long/short ringing.

Someone correct me if I am wrong on the total number, but 8 sticks in my mind, and I am not where I can look it up right now.
-Bill G

poplar1

Quote from: Phonesrfun on November 21, 2013, 12:07:52 PM

Still another way to selectivly ring more than three parties on a line without doubling up with coded ringing was to use the cold cathode tube in series with the ringer and capacitor.  In this case the tube could be biased negatively or positively with line voltage, and then by using the combination of the bias along with divided ringing, the possibilities grew to I think 8 without using coded long/short ringing.

Someone correct me if I am wrong on the total number, but 8 sticks in my mind, and I am not where I can look it up right now.

4 fully selective--8 semi-selective. So with 8 parties, 2 would ring together and would be distinguished  by code--1 long or 2 shorts for example.

+ Tip
-  Tip
+ Ring
- Ring
"C'est pas une restauration, c'est une rénovation."--François Martin.

poplar1

Frequency + capacitance + inductance=
If all values are correct, then you have "resonance" and the ringer responds.
"C'est pas une restauration, c'est une rénovation."--François Martin.

G-Man

Here is a dissertation from Western Electric about frequency ringing and other types of selective ringing. I believe it is circa 1976 and as has been stated the Bell System did not use frequency ringing to often even though they are the ones who first conceived of it.

•   http://www.telephonecollectors.info/index.php/document-repository/doc_details/4706-                telephone-communications-systems-v1-chap-2-early-systems-and-station-equipment-                ringing-extract

Here is another document that gives Automatic Electric's view.

•   http://www.telephonecollectors.info/index.php/document-repository/doc_details/4886-                ae-bulletin-945-804-i1-1963-ringing-schemes

This shows the various ringing codes used by the different types of central offices.

•   http://www.telephonecollectors.info/index.php/document-repository/doc_details/3860-               c63-269-i4-line-ringer-connections


More-

•   http://www.telephonecollectors.info/index.php/document-repository/doc_details/3870-               kellogg-harmonic-telephone-systems-selective-ringing-ad