How the Vocoder Helped Save Us From Nuclear Apocalypse

Guitars and saxophones look cool, stylophones are retro-neat, and nothing helps you say moody loner like a harmonica. But the vocoder does more than just give you a robot voice. In its earliest version, it helped grease the clunky wheels of cryptographic communication that linked some famous non- funk musicians like FDR, Winston Churchill, Harry Truman, and John F. Kennedy with their foreign counterparts. Though the British Prime Minister played a mean vocoder, JFK didn't quite know which button to press.

In his new history of the technology, How To Wreck A Nice Beach: The Vocoder From World War II to Hip-Hop, Dave Tompkins elaborates on how the vocoder helped make our cell phone calls possible and underwrote the ouvre of Afrika Bambaataa. It also pulled its weight – and compressed tons of syllables – during the Cuban Missile Crisis. Here's an excerpt from the chapter titled "Interdiction."

An early vocoder, as seen at the 1939 Worlds Fair

The brink of nuclear annihilation calls for sound advice over a secure phone line, at least one that works properly. On October 25, 1962, John F. Kennedy pushed the button and spoke on the vocoder. While his voice went to the machine, his body was at the pharmacy, infused with steroids, painkillers and anti-spasmodics. He heard a hiss of static and pushed again. At the other end, British Prime Minister Harold MacMillan heard "garble," not, "I don't want to have an incident with a Russian ship tomorrow." While the US Strategic Air Command was at a DEFCON 3 state of readiness—with no secure way to communicate with the ground—Kennedy's Brahmin accent was being transformed into "Mickey Mouse/Donald Duck," a side effect of processing the president's vocal tract into a binary code. Talk of a "Naval interdiction" of all vessels bound for Cuba was compressed and artificially rendered at 1667 bits per second. The letter R was nowhere to be found.

Kennedy had been using the KY-9, a 500-pound 12-channel scrambler developed by Bell Labs in 1953. He often turned to the KY-9 during the Cuban Missile Crisis, a time when a single teletype exchange with Premier Khrushchev in Moscow could take over twelve hours between transmission, decoding and translation, while hung-over Soviet missile commanders sweated it out in submarines and gingerly shuttled warheads across Cuba's harrowing mountain terrain in the dark. Those thirteen days in October were so fraught with miscommunication, Intel glut and near-misses, it's a wonder we're even here to speculate. For the vocoder, there was no shortage of speech-energy breakdowns to analyze. According to transcripts of the Kennedy-MacMillan phone calls, garble came out as "ggrble," as if near gerbil in frequency.

On October 22, after informing Americans about Soviet missile sites in Cuba, JFK called Prime Minister Harold MacMillan in London and General Norstad, then stationed in Paris. MacMillan urged the president to work a compromise with Moscow (don't invade Cuba) while offering support (activate sixty Thor missiles, tipped with US megaton warheads). Norstad, a former WW II pilot who believed "nuclear superiority had limited psycho-political meaning," wanted to immobilize his Jupiter missiles in Turkey, bordering the Soviet Republic of Georgia.

That August, with Soviet cruise missiles and warheads already in Cuba, Harold MacMillan received a classified memo from his secretary Philip de Zulueta: "The Americans have developed a telephone scrambler which promotes secure transatlantic speech. The disadvantage is that the voices sound rather odd." "Temperamental in its habits," the KY-9 was referred to as the "Mac-Jack Line." Conversations were often choppy at best, due to its push-to-talk (PTT) function—fine for buzzing in UPS, yet nerve-wracking on matters of national security. Kennedy would often forget to push or release, leaving dead-air interpretation, perhaps the illusion of tacit consent due to lack of interruption. Cryptography historian David Boak described the KY-9 voice as being artificially restrained. "You…must…speak…very…slowly," he said.

The KY-9 cost $40,000 per unit and had all the charm of an Acme safe, a squat three feet high with a combination dial and light that flashed red for non-sensitive talk and green for crypto. Before activating the vocoder, users were required to say, "Go green!" Instead of sensitive vinyl records—as with SIGSALY—the code key was provided by computer punch cards, with a separate batch reserved for discussing nuclear retaliation. The KY-9 allowed the president to communicate directly overseas without the call being routed through the Pentagon, thus avoiding bureaucratic interference. He enjoyed how his private line aroused suspicion in the State Department, which had its own KY-9 system with separate clearance. If it malfunctioned, Fault Control was contacted and a small set of railroad tracks would release from the back, permitting the vocoder to be trundled out for maintenance. Said one technician, "There was absolutely no possibility of voice recognition."

Excerpted from How To Wreck A Nice Beach: The Vocoder From World War II to Hip-Hop by Dave Tompkins. Copyright 2010 by Dave Tompkins. Excerpted by permission of Melville House/Stop Smiling. This post originally appeared on Motherboard in May 2010.