[GreenKeys] History of modems

[Bruce Gentry]

  In 1970, I saw many of these in use in the Air Force.  One thing that 
caught my attention is that many were built by Wurlitzer.  Because I 
also love theater organs, seeing that name was of great interest. I 
annoyed a lot of people, especially the lifers, when I would see one of 
these and exclaim a 1920s era advertising slogan -   "GEE Dad! It's a 
WurliTzer!!"  One thing I also remember about these modems is they got 
hot as blazes and always smelled like they were on the verge of going up 
in smoke.

      Bruce Gentry, KA2IVY

On 11/7/13 10:26 PM, Jack Hart wrote:
>
> A tremendous source for parts....
>
> Jack K0TTY
>
> *From:*greenkeys-bounces at mailman.qth.net 
> [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of *Duncan Brown
> *Sent:* Thursday, November 7, 2013 8:46 PM
> *To:* greenkeys at mailman.qth.net
> *Subject:* Re: [GreenKeys] History of modems
>
> It is often hard to pinpoint the "first" of anything, but the for the 
> "first" modem, I always think of the US Signal Corps' TH-5/TG:
>
>
>
> This was the Signal Corps' first tactical (came with a water-proof 
> cover) modem and probably the first mass-produced modem. Not designed 
> for civilian telephone lines but used with 2-wire (simplex) or 4-wire 
> (full duplex) field-phone circuits. Designed c1950 for 60/100 wpm 
> teletypewriter circuits and so operated at 42 & 75 bps/baud. Two-tone 
> AFSK: 1275 & 1325 Hz. Uses 15 tubes, mostly 12AU7s & 12AX7s, and 
> weighs about 18 pounds. Contains two 20ma loops - one for RX & one for 
> TX. Contract date is 1951 & first manual date is 1952.  A solid-state 
> version, the TH-22/TG came out about 1967. It was the same size and 
> didn't weigh any less. The TH-5 operator's manual was updated in 1983, 
> so it was apparently still being used then.
>
> Duncan
> K2OEQ
> USASA 31J
>
> On 06-Nov-13 12:06, Jim Haynes wrote:
>
>
>     http://www.techradar.com/us/news/internet/getting-connected-a-history-of-modems-657479
>
>
>     jhhaynes at earthlink dot net
>     ______________________________________________________________
>
>
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