[Milsurplus] overheard telephone conversations

[Robert Newberry]

One of those SXS step by step systems is on display the the antique
wireless museum in Windsor, CT. You can place a call to a phone on the
other end of the room and see it work. Pretty neat place.

N1XBM
Apparare Scientor
Paratus Communicare
Allstar Node # 27086, 41540, 41812, 42086, 42658, 42657
www.radioguysrepeaternetwork.com
On May 31, 2016 7:13 PM, "Hubert Miller" <kargo_cult at msn.com> wrote:

> I wonder how much if anything of those FDM systems survives. Not very
> practical for demonstration, i suppose. Compared to telco switching
> equipment.
> ( A former co-worker has his own 1000 line telephone step-by-step (SXS)
> 'central office' on his property - calls it "Turnerville" )
> -Hue
>
> -----Original Message-----
> From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of
> AKLDGUY .
> Sent: Tuesday, May 31, 2016 3:50 PM
> To: milsurplus <milsurplus at mailman.qth.net>
> Subject: Re: [Milsurplus] overheard telephone conversations
>
> The consensus seems to be that WW2 necessitated encryption and spurred on
> its development, but there's nothing to suggest that 1937 radio telephone
> calls were made unintelligible to the casual HF listener.
>
> It doesn't even seem clear whether SSB was used. Terrestrial telephone
> links
> certainly used upper sideband in broadband Frequency Division Multiplex
> systems pre-war, as I pointed out in an earlier post where I described the
> Western Electric crystal filters. I just now recalled that those filters
> had
> the ring modulator or demodulator (depending on speech direction) built-in,
> together with impedance matching transformers.
>
> 73 de Neil ZL1ANM
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