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Author Topic: Rebuilding a Piece of the First Digital Voice Scrambler  (Read 298 times)

Offline ChrisSmolinski

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Rebuilding a Piece of the First Digital Voice Scrambler
« on: February 16, 2019, 1928 UTC »
In the years before World War II, German intelligence could decode band-scrambled U.S. radiotelephone conferences. After Pearl Harbor, an unbreakable speech scrambler was developed with top priority, and by 1943, it was deployed. Known as SIGSALY, the device pioneered many advances critical to modern digital media technologies, including spread-spectrum communications and the first use of pulse-code modulation (PCM) to transmit speech.

SIGSALY was top secret, so even today information about the details of its construction are hard to come by. I’ve spent 20 years researching the history of digital technology and digital media, especially SIGSALY. I searched IEEE and U.S. National Security Agency (NSA) journals, and Bell Telephone Laboratories patents. Finally, I found Lieut. Donald Mehl, a WWII SIGSALY technician, who gave me invaluable assistance. In 2015, I realized that it might be possible to re-create a key element of SIGSALY—the quantizer—using vintage parts.

SIGSALY was unbreakable because, unlike earlier analog systems, it scrambled voices by using a one-time random digital encryption key. Before a digital key can be applied, a speaker’s voice must first be converted from analog to digital, thus the quantizer.

Full article: https://spectrum.ieee.org/geek-life/hands-on/rebuilding-a-piece-of-the-first-digital-voice-scrambler
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
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Offline Josh

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #1 on: February 16, 2019, 2042 UTC »
Neat, went looking for off the air recordings of sigsaly but no joy.
Conveniently located near Vincennes Indiana.

Offline Pigmeat

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #2 on: February 17, 2019, 0039 UTC »
"Quantizer???" Sounds like it's related to ol' Doc Fansome's flux capacitor technology.

Offline Azimuth Coordinator

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #3 on: February 17, 2019, 2146 UTC »
Another Bell Labs Innovation..   Ah I miss the old days..
QTH: A Clandestine location on the East Coast
Watkins Johnson WJ-8716, WJ-8718A, WJ-8618B
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Offline Pigmeat

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #4 on: February 18, 2019, 1739 UTC »
Another worshiper of the Cult of Ma Bell.

Offline Josh

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #5 on: February 18, 2019, 1900 UTC »
Lol my mom dragged me to a few ma bell strikes as a kid, hated unions ever since. Eventually bell morphed into US West and she was finally happy.
Conveniently located near Vincennes Indiana.

Offline Azimuth Coordinator

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #6 on: February 18, 2019, 2303 UTC »
Another worshiper of the Cult of Ma Bell.


Cult you say...  I thought we kept that a Secret..  BTW  I'm a Bell Labs Veteran 15+ years .. Would you like to come over for some Tang..  We don't drink Kool Aid any more  ;D ;D
« Last Edit: February 18, 2019, 2322 UTC by Azimuth Coordinator »
QTH: A Clandestine location on the East Coast
Watkins Johnson WJ-8716, WJ-8718A, WJ-8618B
Radio.Illuminati6150@Gmail.com

Online redhat

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #7 on: February 19, 2019, 0146 UTC »
You can keep the Tang, but if you've got a few greenies laying around I'll trade ya ;)

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Offline Pigmeat

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Re: Rebuilding a Piece of the First Digital Voice Scrambler
« Reply #8 on: February 19, 2019, 1221 UTC »
As it seems most of us on this thread are older than dirt, do any of you guys remember the "voice changers" they used to sell in hobby shops? They looked like two metal bottle caps mashed together. More than one pirate used those dime store cheapies to sound different on the air.

Not me, of course. I used a toilet paper tube method with one end covered by split wax paper. Stick two crayons up your nostrils and raise the tone of your voice as you speak in the mic.  If you've got a manly bass-baritone voice, like me, it will make you sound just like Commander Bunny. Used to drive Al crazy when Radio Al Fansome ruled the airwaves.