The Secret History of Phone Bugs

The Birth of Electronic Eavesdropping

In the shadowy world of espionage, few tools have been as pervasive—or as controversial—as the humble phone bug. The first documented use of electronic eavesdropping dates back to the early 20th century, when crude wiretaps were employed by law enforcement to intercept telegraph and telephone communications. By the 1920s, advancements in radio technology allowed for more sophisticated bugs, enabling spies and detectives alike to listen in on conversations from a distance.

One of the earliest known cases involved the U.S. government using wiretaps during Prohibition to track bootleggers. But it wasn’t long before these devices fell into the hands of private investigators, corporate spies, and even organized crime. The phone bug had arrived—and it was here to stay.

Cold War Espionage and the Golden Age of Bugs

The Cold War marked the golden age of phone bugs, as intelligence agencies on both sides of the Iron Curtain raced to develop ever-more-sophisticated surveillance tools. The KGB and CIA invested heavily in miniaturization, creating bugs so small they could be hidden in everyday objects—telephone handsets, lamps, even the heels of shoes.

One infamous example was the “Great Seal Bug,” a listening device planted inside a wooden replica of the U.S. Great Seal, gifted to the American ambassador in Moscow in 1945. For seven years, Soviet agents eavesdropped on sensitive conversations before the bug was finally discovered. Meanwhile, the CIA developed its own arsenal of covert bugs, including the “infinity transmitter,” which could activate a phone’s microphone even when the handset was hung up.

From Analog to Digital: The Evolution of Surveillance

With the advent of digital technology in the late 20th century, phone bugs underwent a radical transformation. No longer confined to physical devices, surveillance shifted to software-based interception. Governments and hackers alike exploited vulnerabilities in telecom networks, enabling mass data collection without the need for physical bugs.

The revelations of Edward Snowden in 2013 exposed the extent of modern electronic surveillance, showing how intelligence agencies could tap into phone calls, texts, and internet traffic on a global scale. Yet, despite these high-tech advancements, old-school phone bugs still have their place—whether in corporate espionage or high-stakes criminal investigations.

The Ethics of Eavesdropping

The history of phone bugs is as much a story of technological innovation as it is a debate over privacy and ethics. While law enforcement agencies argue that surveillance is essential for national security, civil liberties advocates warn of the dangers of unchecked eavesdropping.

As we move further into the digital age, the line between security and intrusion continues to blur. One thing is certain: the secret history of phone bugs is far from over.

“The walls have ears”—but in the modern world, so do our phones.