Foreign Relations of the United States, 1961–1963, American Republics; Cuba 1961–1962; Cuban Missile Crisis and Aftermath, Volumes X/XI/XII, Microfiche Supplement

377. Telegram 987 to Moscow, October 24¹

October 24, 1962, 2:52 a.m.

Request following regulation of Secretary of Defense be transmitted to Soviet Government:

“Pursuant to Proclamation of the President of October 23, 1962, on the ‘Interdiction of the Delivery of Offensive Weapons to Cuba’ the Secretary of Defense has today issued the following submarine surfacing and identification procedures when in contact with US quarantine forces in the general vicinity of Cuba. US Forces coming in contact with unidentified submerged submarines will make the following signals to inform the sub that he may surface in order to identify himself:

Signals Follow—Quarantine Forces will drop four or five harmless explosive sound signals which may be accompanied by the international code signal “I D K C A” meaning “rise to surface.” This sonar signal is normally made on underwater communications equipment at the 8 XS frequency range.

Procedure on receipt of signal:

Submerged submarines, on hearing this signal, should surface on easterly course.

Signals and procedures employed are harmless.

Other governments being similarly informed.

Rusk

1. Transmits regulation of Secretary McNamara re submarine surfacing and identification procedures used by U.S. quarantine forces in vicinity of Cuba for transmittal to Soviet Government. Unclassified. 2 pp. OSD, Historical Office, Secretary of Defense, Cable Files, Cuba, Oct. 23–24, 1962.