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The Telecom Digest for December 11, 2010
Volume 29 : Issue 334 : "text" Format

Messages in this Issue:

Donations Ban on iPhone Apps Irritates Nonprofits(Monty Solomon)
Re: Question about an old scrambler phone(Ernest Donlin)

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Date: Fri, 10 Dec 2010 01:10:12 -0500 From: Monty Solomon <monty@roscom.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Donations Ban on iPhone Apps Irritates Nonprofits Message-ID: <p06240823c927746b0d40@[]> Donations Ban on iPhone Apps Irritates Nonprofits By STEPHANIE STROM December 8, 2010 The nonprofit world is stewing over the ban Apple has put on making donations on the iPhone via charity apps. No one, including Apple, has data on how many nonprofits have created apps for the iPhone. Organizations like the Monterey Bay Aquarium and American Cancer Society have them, but none can be used to make gifts. Prospective donors instead are directed out of a nonprofit's app and to its Web site, which the organizations say makes the process of contributing more cumbersome. ... http://www.nytimes.com/2010/12/09/technology/09charity.html
Date: Fri, 10 Dec 2010 19:31:19 -0500 From: Ernest Donlin <ernest.donlin.remove-this@and-this-too.gmail.com> To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org. Subject: Re: Question about an old scrambler phone Message-ID: <AANLkTikNo4yk2IrcNuKp_F8QRugnedkZuknL1PEFju-E@mail.gmail.com> On Wed, Dec 08, 2010 at 06:38:59AM -0600, Robert Bonomi wrote: > In article <AANLkTikNo4yk3iRENuKp_f4QRTgnedkZuknL1PEFju-E@mail.gmail.com>, > Ernest Donlin <ernest.donlin.remove-this@and-this-too.gmail.com> wrote: > >(moderator please change my email address so spammers can't use it.) > > > >I've got an odd sort of a question for your group. > > > >When I was a kid, my friend's dad had a phone in his house that he told me > >was a "scrambler". It was a regular telephone, mounted on a metal > >base, with an AC cord for the base. The base had just two vacuum tubes in > >it, and a couple of transformers. It didn't look like much, but my friend > >said his dad used it to make scrambled phone calls to his reserve unit. > > > >Has anyone ever seen anything like that? I never knew if he was yanking my > >chain or not. > > One of the simplest forms of a 'scrambler' simply frequency-inverted the > audio input. basically, use the audio to AM modulate a circa 4kHz 'carrier', > and send only the the lower sideband over the wires.. > > Conveniently, you can 'unscramble' the signal by doing exactly the same > thing to the 'scrambled' signal. > > Necessary components are: 1) an oscillator, 2) a modulator, 3) a low-pass > filter. That's two tubes, and an inductor with a couple of capacitors, > plus a multi-tap (filament and B+) power transformer to run it all. > > Sounds real close to what your friend's dad had. <grin>> > > Now, to answer the actual question you asked: "No, I've never actually > seen one of them myself." I only know "of" such devices, having read > about, seen schematics in books, etc. Thanks, that's nice to know. I didn't think my friend would go to all that trouble to put a box and tubes, etc. on the bottom of a phone, but it still seemed so simple a circuit that I couldn't quite believe it would work. Now, I'm curious: is that kind of scrambling still possible? It seems like it would be a neat way to keep the kids from picking up the phone when I want to gab with the wife. I'm not going to build one, but I wonder if there's anything I can buy online? Thanks for helping. -- Ernie Donlin
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