Limousine Microphone 1935-1940 ?

[RichMig61]

My family has this microphone which supposedly is from my grandfathers limousine, likely a LaSalle or Pierce Arrow.  I think the year is 1937 give or take.

 

Can anyone confirm this and identify the car it came from?

 

Had trouble attaching the photo's.  Uploaded them to my box account instead.  https://app.box.com/s/4xic3ok3hgch4p19l8q0pqzz520cil8y

 

Thank you in advance.

 

[JimKB1MCV]

I suspect the microphone is probably generic aftermarket since the intercom systems (I think) were supplied by the body builder or dealers. It works on the same principal as a public address system, just at a reduced output to communicate with the driver.

 

The mic looks very much like the crystal mics used by amateur radio operators of the period and still used to an extent today.

 

There should be a power supply and a speaker system with the mic, do you have them?

[RichMig61]

1 hour ago, JimKB1MCV said:

I suspect the microphone is probably generic aftermarket since the intercom systems (I think) were supplied by the body builder or dealers. It works on the same principal as a public address system, just at a reduced output to communicate with the driver.

 

The mic looks very much like the crystal mics used by amateur radio operators of the period and still used to an extent today.

 

There should be a power supply and a speaker system with the mic, do you have them?

Thanks for the response. We just have the microphone.

[RichMig61]

[DavidMc]

Its a "Dictograph" microphone originally connected to a recoil unit and speaker fitted to the 1930 Packard 740 Limousine  and other makes of cars.  It allowed the passenger to instruct the chauffer, when the division window was closed, the chauffer had the speaker but no microphone to respond