"SIGSALY" OR "THE GREEN HORNET"
A HIGH SECURITY VOICE COMMUNICATIONS SYSTEM
USED IN GHQ SWPA, BRISBANE

 

By 1 November 1943, a high security voice communication system known as RC-220-T1 or "Sigsaly" was installed by the 805th Signal Service Company. "Sigsaly" was used by General Douglas MacArthur and his staff at his General Headquarters in the AMP building in Queen Street in Brisbane during WWII. "Sigsaly" was located in the basement of the AMP building. It allowed secure voice communication to Washington, London, Algiers and other locations in Australia for MacArthur and his staff.

"Sigsaly" was developed for the War Department by Bell Laboratories. "Sigsaly" was also know as "The Green Hornet" or the "X system". It was the first unbreakable scrambler for radio messages used by the military. President Roosevelt could pick up his telephone and talk to Churchill and MacArthur, or MacArthur could make contact with the War Department in Washington without the enemy listening in. The Germans did in fact monitor "Sigsaly" for two years but were never able to unscramble the voice communications.

Sigsaly relied on the Army Command and Administrative Network (ACAN) for its radio links via the Capalaba Radio Receiving Site and the Redlands Bay Radio Transmitter site which was later replaced by the Hemmant Radio Transmitter Site.

All of the "Sigsaly" equipment was returned to the USA after the war and destroyed. It took until 1976 before information on "Sigsaly" was declassified by the American government.

Here is an interesting excerpt from "General Kenney Reports" by George C. Kenney, 1949.

"On the 9th of November, 1943, a direct telephone line between Brisbane and Washington was inaugurated. General Barney Giles, Arnold's Chief of Staff, talked with me for a few minutes and mentioned that my son, Bill, who had recently graduated from Officers Candidate School and been given commission as Second Lieutenant in the Air Corps, was on his way to the Pacific. I told him not to send Bill to me as it would not be fair to either of us. I said to send him to the Thirteenth Air Force and let him work for General Miff Harmon. Barney said he would fix the orders up and then he put Alice Kenney, my wife, on the line. The connection was not too good, and I had trouble understanding her excited soprano voice, but we both got quite a kick out of the conversation. Arnold had very thoughtfully brought her in for the occasion, warning her that the very existence of the newly opened line was a deep military secret. She told me afterward that she was so impressed she didn't dare mention it even in her diary."

 

 

YouTube Video - Encryption - Sigsaly

 

ACKNOWLEDGMENTS

I'd like to thank Bill Bentson for his assistance with this home page.

 

BOOK REFERENCES

"Top Secret Communications of World War II"
by Donald Mehl

 

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 Peter Dunn 2015

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This page first produced 12 October 2001

This page last updated 09 February 2017