49-500 test results.

[Greg G.]

I was late getting to the museum, so the test wasn't as thorough as I had planned, but managed to test it's functionality and also experiment with that switch. I also forgot to bring my camera, so I made notes on an earlier picture.

After some minor reconfiguring of a wire or two with the help of Bill Guerts, I'm happy to report that it fully functions.  Bill had to leave right after that but before I could mess with the switch wires.

Don and David of the museum staff helped me with that. Don rigged the phone up to a power kill switch so I wouldn't have to keep plugging it in and out when I wanted to power it on and off.

The two wires on the switch (1 long one, 1 short one) are only long enough to reach the equalizer.  I took my best guess at where they went.  The short one appeared to be meant for the nearest terminal, so I hooked it up to that.  When I picked up the longer one, it was shaped with a curve that made it appear that it was hooked up to the terminal just to the right, so that's where I put it.

With the power on (cover off) and while the phone was on-hook, I turned the switch and just observed, nothing.  I took the phone off-hook and when I turned the switch to the horizontal position, I heard a small click in the receiver and observed that a small light came on in the equalizer that you could see coming out the bottom and also through a hole in the top.  I also noticed that the dial tone got louder/softer when the switch was turned, but it didn't mute the dial tone entirely.

Next step was to call the 49 from a nearby extension with David answering the 49. He spoke as I turned the switch on and off, and we noticed that the volume was louder or softer depending on which position, but it didn't mute it.  I'm sorry I didn't take better notes, but I can't remember which position was loud/soft, but that's what it did, and it was on both ends, the extension and the 49. I also wanted to see what happened if I moved the long wire to a different terminal, but I was exhausted and running late, so that's as far as I got (for now).

So the moral of the story is that the switch function is still to be determined because I wasn't able to try the two wires on different terminals.

[G-Man]

This is a bit confusing, could you provide further information such as:

What is the pupose of your experiment?
What is the name of the museum?
What is the overall context?

I presume the telephone is a 500-set manufactured in 1949.

Thanks

[Greg G.]

This is a bit confusing, could you provide further information such as:

What is the pupose of your experiment?
What is the name of the museum?
What is the overall context?

I presume the telephone is a 500-set manufactured in 1949.

Thanks

Here's the history of it on this forum:  http://www.classicrotaryphones.com/forum/index.php?topic=2689.0

There was also an article in the Singing Wires in the June 2010 issue.  There was much speculation about the function of the switch.

[Phonesrfun]

A short answer is that we were trying to determine the purpose behind the switch in the early 500 set.  Yes it is a 1949 early production set with the equalizer.

The switch was disconnected so we did not know what its intended purpose was.  The section of the switch that has wires soldered to the switch leaves is just one SPST section that turns on when turned and off when turned back.  The wires appear to be original to the switch, and there are no other wires attached to the switch, as the solder tabs on the switch leaves are bare metal and have never had any wires soldered to them.  The switch appears to be original to the phone and to the phones shell.

The questions were as to whether the switch:

Muted the transmitter,
Muted the receiver,
Turned on/off the transmitter
Turned on/off the receiver

Since the transmitter is in series with the equalizer lamp inside, turning off the transmitter would probably not have done any good.... It would probably cause a disconnect.  Shorting the transmitter might cause the equalizer lamp to draw too much current and risk burning out.

Maybe it was to mute (short) the receiver.

Better yet, maybe they put it there to make us ask questions 63 years later. 

Unfortunately, there is no number on the bottom of the phone to tell us what it was for.

[Dan/Panther]

If'n we is gonna pays you guys big bucks, to do these field research programs, we expect more data in return.
D/P

[Greg G.]

If'n we is gonna pays you guys big bucks, to do these field research programs, we expect more data in return.
D/P

My methodology is quite scientific, using the "by guess and by golly" approach.

[Phonesrfun]

I guess ya gets what ya pays fer.

[Greg G.]

If anybody really wants to do a detailed technical analysis, which would make an interesting followup article for SW, I'm sure the museum staff would be more than willing to accommodate you, and I would be more than happy to assist whatever way I can if I'm available, even if it's just buying you lunch.  Such an analysis would not come from me, I have no training in electronics and the most sophisticated equipment I have is an ohmmeter from Radio Shack, otherwise I would have done one.

[AE_Collector]

even if it's just buying you lunch.

You did a good job at supplying the coffee on Saturday so you would probably do even beter at Lunch!

[Dan/Panther]

Just have the museum send the phone to me and I'll give a detailed report.
Gheez, I wonder if they'd trade for the D-177 ?
D/P