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Convertible 10/12-Button Touch Tone Dials

Started by Dave F, November 02, 2010, 03:52:48 PM

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Dave F

By 1968, W.E. had begun installing "convertible" touch tone dials into most new-production 10-button sets.  Phones with the new dials could easily be field-converted to 12-buttons sometime later when special services requiring the two new buttons were developed.  Parts kits containing the extra buttons, collars, and springs were available as special-order items.  The 25A3 dial, used in 1500 and 1554 sets, was replaced by the 25W3 convertible dial.  Other similar replacements included 25Y3 for keysets and 25R3 for Card Dialers.  The 25H4 illuminated dial used in Princess phones was superceded by the 25P4 convertible.  The special field kits for these dials were D-180115 for non-illuminated dials, and D-180116 for the Princess dials.  More info on this topic can be found in BSP 501-164-105, issue 5.

Most of us who have looked inside a 10-button Touch Tone phone have probably run across a convertible dial at one time or another.  These are common and easily identified by the part number and by the gray tape covering the unused extra button holes.  However, dials which actually were converted to 12-buttons are very rare.  By the time that there was a real need to use the extra buttons, the 2500 set was in production, and the convertible dials became a short-lived footnote in Bell System history.

In 1968, I was building a phone patch radio repeater (early car phone) for my senior engineering project at UCLA.  I wanted to use the two extra buttons on a Touch Tone dial to control the remote operation of the repeater.  Fortunately, W.E. was willing to assist me, and sent me several things.  Included in the goodies they sent were two of the conversion kits, which you can see in the photos below.  I have had these in my collection for more than 40 years and, to this day, these are the only specimens I have ever seen.

A footnote:  Inspect all your 2500 sets carefully.  If you find one that says 1500D on the bottom, you might possibly have in your possession one of the rare converted dials.

HarrySmith

Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

paul-f

Installation instructions and more details on the kit of parts can be found in BSP 501-164-105 - found in the TCI Library.

Early 25-type dials were not convertible, while later models had the holes for the two extra buttons covered with tape.

12-button dials are occasionally found that have 25-type markings and less color fading on the two added buttons, if the upgrade was done after several years of use... (2nd photo).

Visit: paul-f.com         WE  500  Design_Line

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ESalter

That's really interesting.  I've seen the 10 button dials with the stickers on them, but I didn't realize that was why.  I know I have a 2554 that's marked as a 1554 on the back, I'll have to open it up and check it out.

Dan

So does this look like one of the converted ones to you Dave?

"Imagine how weird telephones would look if our ears weren't so close to our mouths." - Steven Wright

paul-f

It's certainly worth taking the faceplate or housing off to take a closer look!
Visit: paul-f.com         WE  500  Design_Line

.

Jim Stettler

I have always assumed the curvered "operator" on a 10 button WE set was an indication of a converted dial.
Jim
You live, You learn,
You die, you forget it all.

Dave F

#7
Quote from: Dan on November 02, 2010, 09:05:02 PM
So does this look like one of the converted ones to you Dave?
Could be!  We're eagerly awaiting your report.  Yank that cover and let's have a looksee!!

By the way, the housing on your red phone is much newer than the dial, which has the older "operator" spelled out.  Obviously, that housing has been changed sometime in the past.

Dave


Dave F

Quote from: Jim S. on November 02, 2010, 09:31:36 PM
I have always assumed the curvered "operator" on a 10 button WE set was an indication of a converted dial.
Jim
No Jim, all the early 10-button (type 25) dials had the curved "operator" spelled out, as did the first 12-button (type 35) dials as well.  The only way to know for sure if a 12-button dial is actually a converted 10-button is to remove the faceplate and visually inspect it.  If it's a 25W3 or 25P4 with the installed extra parts, you've found a winner!

Dan

well, my dial is a 35A3A dated 3-68. Next to it is a sticker that says 12C-78. What does that mean?
"Imagine how weird telephones would look if our ears weren't so close to our mouths." - Steven Wright

Dave F

Quote from: Dan on November 02, 2010, 10:22:10 PM
well, my dial is a 35A3A dated 3-68. Next to it is a sticker that says 12C-78. What does that mean?
Shucks, close but no cigar.  Unfortunately, that's what 99.9% of these things turn out to be.  The sticker probably refers to a 1978 refurb date.

McHeath

That's very cool that you still have those items from your late 60's project.  I've got a couple of 10 button dials without the conversions but with the holes for them, and I've never seen a conversion kit in person.  You've got a nice piece of history there. 

Dave F

Quote from: McHeath on November 02, 2010, 10:39:50 PM
That's very cool that you still have those items from your late 60's project.  I've got a couple of 10 button dials without the conversions but with the holes for them, and I've never seen a conversion kit in person.  You've got a nice piece of history there. 
Back in the mid 1970s, I got rid of a lot (but not all) of my phone stuff.  After some time had passed, I was really sorry that I had done that, and it still gnaws at me now.  But some things have survived, and I get a thrill every time I open an old box and discover some new treasure from the past.  The dial conversion kit for the illuminated dial is particularly rare, as those were only used on Princess phones.  I had a Princess phone in my car, and the dial would light up along with the dashboard lights.  A direct-dial car phone was pretty special in 1968.  It was a real kick to order pizza delivery while watching a movie at the drive-in.  The pizza guys would deliver it right to the car.  Yup, thems were the dayz!!

When I was building the repeater, I tried to get Pacific Telephone to help out with some parts, but they basically told me to get lost.  In fact, I was actually given a lecture about not connecting any of my "homemade" stuff to the phone network.  Fortunately, my request directly to Western Electric (on UCLA Engineering Department letterhead) had better results.

Jim Stettler

Quote from: Dave F on November 02, 2010, 10:13:25 PM
Quote from: Jim S. on November 02, 2010, 09:31:36 PM
I have always assumed the curvered "operator" on a 10 button WE set was an indication of a converted dial.
Jim
No Jim, all the early 10-button (type 25) dials had the curved "operator" spelled out, as did the first 12-button (type 35) dials as well.  The only way to know for sure if a 12-button dial is actually a converted 10-button is to remove the faceplate and visually inspect it.  If it's a 25W3 or 25P4 with the installed extra parts, you've found a winner!

I was wondering if that was the case. An early 12 button dial is still a nice find, I like the backpainted plates.

Thanks,
Jim
You live, You learn,
You die, you forget it all.