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--- On Wed, 6/3/09, Dave Lewis <[log in to unmask]> wrote:


> There is a device at Greenfield Village here in Michigan
> that is a pair
> of flat copper discs -- square -- on paired turntables...

> I would love to know if this device makes any audible
> sound, and of
> course, what the messages are on the discs.

Edison himself said that he was inspired to work on
the phonograph after hearing sounds reminiscent of
speech coming from a high speed telegraph repeater.
As I recall, it was a similar disk-based device.
The telegraph message would be recorded on it at
"human" speed and send down the wire greatly sped up.
It was recorded at the receiving end and played
back again at the "natural" speed for a telegrapher
to transcribe.

I saw a similar device to this in the 1980s for a
Teletype ASR-33.  The operator keyed the message(s)
onto paper tape as usual, then instead of sending
the message via the teletype itself, ran the tape
on a high-speed transmitter that relayed the
message to the destination at a blinding 1200 baud! :-)
The tape created at the remote end was then send
through another teletype in local-loop mode to print
out the message. (A regular ASR-33 operated at 110 baud.)