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 Western Electric Rotary (Pulse) Dials

 

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We've had several visitors to the web site ask how to remove the finger-wheel on a rotary dial telephone they just bought on eBay, thrift store, flea market, garage sale, etc.  Well, I hope to provide some help in this area of telephone collecting/restoration with a little help from my friends in the two clubs I belong to.  Even though touch-tone telephones became available in the mid 1960's, rotary dial phones were still in common use in the 1980's and some die-hards are still using rotary dial phones (like us collectors!) in the second millennium!

The irony of rotary verses touch-tone is that rotary dials produced DIGITAL data that was used by the equipment in the central office whereas today's modern touch-tone dials produce ANALOG signals.  All the hype about us being in the digital age is not true of our touch-tone phones - until we get to the central office where the tones are converted to digital format.  So when someone asks you why you have an old-fashioned rotary phone, simply tell them that it's really very modern since it's dial is digital and not analog!  Who would be caught dead with an old analog touch-tone dial when they could have a "modern" digital dial! :-)

Plastic Finger Wheel

If you want to know how to remove the number card in your old rotary phone with the plastic finger-wheel, click HERE for instructions in GIF file format or HERE in PDF file format (courtesy of R. Wiltfong and Steph Kerman, respectively.) 

For photos of removing the wheel from a Princess phone (type 8FA dial), click on the following hyperlinks:

Paper clip shown in hole of finger wheel

Close up view of paper clip hole

Close up view showing retainer tab dislodged from notch in finger wheel

Photo showing finger wheel removed, exposing wheel hub

Photo showing edge view of finger wheel notch area with tab in normal position

Photo of finger wheel upside down to show details of notch and "retainer tab ramp" which is what the tab slides along just prior to latching in position in the notch when finger wheel is re-installed.

Metal Finger Wheel

We have scans of the front and back of one type of metal number-card retainer on a model 500 set.

There is another type of number card holder/retainer which is on a Western Electric model 302 telephone I have:

Photo showing location of release tab of number card holder assembly

Photos of disassembly process:
Photo A - Photo B - Photo C - Photo D - Photo E


 Another photo of dials that might be of interest.



We have some photos and direct scans of various dials (mostly Western Electric).


Dial pulses consist of momentary opens in the loop; dial pulses should meet the following standards:

Pulse rate: 10 pulses/second +/- 10%
Pulse shape: 58% to 64% break (open)
Inter-digital time: 600 milliseconds minimum

NOTE: Two pulses indicate the digit "2", three pulses indicate the digit "3", and so on up to ten pulses indicating the digit "0".


The following information was provided by Steph Kerman:

"Dials used on the Western Electric 500 and 554 series were originally #7, later #9 and finally #9xA.

  • #7 has a die-cast frame and metal gears. Number plate is attached with screws. Metal finger wheels on black dials, plastic on colored ones.
     

  • #6 dial is a 3" dial for pre-500 sets using similar construction to a #7 dial. They were used in some 5302 sets but that's not really a 500 set.
     

  • #9 has a stamped frame and some or perhaps all plastic gears. # plate attached with a locking ring. Plastic finger wheels on all color dials as far as I know.
     

  • #9xA has even more plastic parts. # plate locks on by rotation and is held by the finger stop. Plastic finger wheels on all color dials as far as I know. By the way, the 9xA number plate is a retrofit for #7 dials. The #9 number plate fits the #9 only.

    Most 500-series set dials have 4 wires. Those intended for telephone sets with speakerphones have 6 wires."
     

The simplest rotary dials have only two sets of contacts; one set generates the dial pulse, the other set mutes the receiver in the handset so that the load popping sounds created by the dial pulsing contacts will not hurt the users ears.  In other dials, such as the 5H series used in the Western Electric 302 telephones, there is a third set of contacts.  What is this third set used for on the 5H dial?

  • "It short circuits the primary of the induction coil." - sk

  • "The extra set of off-normal form A contacts (which are connected to the yellow leads) are to mute the speaker of a speakerphone set up." - apb

 

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