Your article in the Winter 2023 issue of Vietnam magazine [“The Enemy Listened In”] prompted a memory from when I attended the Infantry Officer Basic Course at Fort Benning in 1978. During our class on OPSEC, the instructors played a film clip with audio that showed an example of Imitativeconfusion that followed as the command group attempted to verify the friendly unit and its location with higher headquarters. The instructors familiar with the incident stated the delay and confusion allowed a Viet Cong unit time to escape back to its sanctuary in Cambodia. I looked up this incident online after reading your article and found that it took place in January 1968 and involved an infantry battalion from 2BDE, 25ID. Known as the “Australian ICD incident,” the voice continued to confuse the Americans for several days until H&I [harassment and interdiction] fires were called on several possible locations. No trace of “the Australian voice” was found. Evidently, this voice continued to harass U.S. and allied units for several months until early 1969. Australians who listened to the tapes verified that the accent was authentic and that the person, who was never identified, was a real Australian. During my tour in El Salvador as a senior adviser to the ESAF during the civil war (1979–1992), the guerrillas used ICD quite often in attempts to confuse the advisors and our counterparts during combat operations.
