The hotline did not ring

On August 30, 1963, the United States sent the first test message over the new Washington–Moscow hotline:

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It was not presidential wit. The sentence and digits exercised every key on the American teleprinter. Moscow replied with a Russian test of its own. The most consequential communications link in the world began by confirming that it could print an alphabet.

The hotline was not a red telephone. Its original form was a full-time duplex telegraph circuit running from Washington through London, Copenhagen, Stockholm and Helsinki to Moscow, with a radiotelegraph route through Tangier as backup. The 1963 agreement specified page printers, transmitters, reperforators, encoding equipment, spare parts, tools and a year’s supply of technical literature.

There was a neat exchange. The Soviet Union supplied Washington with the equipment needed to receive Russian. The United States supplied Moscow with the equipment needed to receive English. Each side’s words would arrive on machinery provided by the side that wrote them.

Text was not an inferior substitute for the telephone. It was part of the safety design. A voice call would require rapid interpretation while two leaders improvised under pressure. A printed message could be translated, checked and considered before anyone answered. The circuit reduced delivery time from hours to minutes without requiring the reply to be instantaneous.

That distinction tends to disappear in the image of the red phone. A telephone promises access to a person. The hotline promised reliable delivery to an institution: the agreement required each government to ensure that a received communication promptly reached its head of government.

The daily tests proved that the machines and route were ready. In an actual crisis, the useful feature was not that the presidents could suddenly talk. It was that neither had to.