"Sigsaly" or "The Green Hornet" - a high security voice communications system used in GHQ, SWPA, Brisbane

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

visits since 12 October 2001

By 1 November 1943, a high security voice communication system known as "Sigsaly", was used by General Douglas MacArthur and his staff at his General Headquarters in the AMP building in Queen Street in Brisbane during WW2. "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.

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.

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