The hourglass curve of this rectangular baffle muffles conversations on a candlestick phone so only the receiver can hear on the other end of the line. [Photo: Spark Museum of Electrical Invention]

It’s not unusual today to overhear strangers’ intimate phone conversations while commuting to work on public transit, or when relaxing in a park. Wireless telephone devices also give us the luxury of seeking out a quiet space where no one can listen in on a private phone call, or taking calls on the move.

But in the early 1900s, as businesses began adopting telephones and conducting meetings by phone, people began to run into an uncomfortable issue: eavesdropping. The first telephones strapped people to their desks, transforming the office into a space where everyone could snoop on conversations aired out in the open. Unfamiliar with the new conditions, many workers felt as if their privacy was being infringed upon.

“Today, it’s not a big deal if your coworker heard you talking to another customer,” says John Jenkins, co-founder and president of the Spark Museum of Electrical Invention in Bellingham, Washington “But back then, phones were so different and new. [People] were used to this face-to-face interaction, that it felt very much like they were being violated.”

To create more privacy, callers could attach a Hush-A-Phone, a rectangular, metal chamber—or baffle—that concealed conversations from others in the room.

A Hush-A-Phone propped on a candlestick phone on display at the Spark Museum of Electrical Invention. [Photo: Spark Museum of Electrical Invention]

Invented in 1921, the Hush-A-Phone was advertised as a “telephone silencer” and a device that “Makes your phone private as a booth.” It produced the same effect as cupping both your hands around the mouthpiece of the two-pieced candlestick model telephone, with others in the room only hearing a rumbling of indiscernible sounds.

Callers only needed to slide the Hush-A-Phone over the mouthpiece of the phone, place their lips in the circular opening, and speak. The device was simple, easy to use, and it worked. Yet, the Hush-A-Phone isn’t remembered for its simplicity, or success in creating an artificial cone of silence. Rather, the device is known for waging a war against the telecommunication giant, AT&T—a historic legal battle law experts compare to feuds over today’s open internet.

“Hush-A-Phone is probably one of the more well-known cases,” says Jenkins. “I don’t know if it’s the first, but it’s certainly one of the most prominent.”

The open internet, also referred to as network neutrality, is an ideology endorsing the freedom of people to browse and consume any content on the web at any time without interference from internet service providers. It is opposed to companies that would slow down data speeds of certain users, or allow some sites and content to load faster than others.

During the most recent push for open internet, experts began dusting off and revisiting the story of the Hush-A-Phone, which became relevant due to AT&T’s exclusion of the device, and subsequent monopolization of the telecommunication market. “It’s famously cited in law school textbooks and was used as an example during the internet freedom movement,” says Jenkins.

In June 2015, the Federal Communications Commission (FCC) agreed to support an open internet, and vowed to protect “open, uninhibited access to legal online content without broadband internet access providers being allowed to block, impair, or establish fast/slow lanes to lawful content.”

Unfortunately for Hush-A-Phone customers, there was no such protection from the powerful phone companies that would limit and even stop providing service if such accessories were used. The obscure, unsuspecting Hush-A-Phone became a victim in AT&T’s inexorable need to control the telecom world.

Using the Hush-A-Phone was like having your own private phone booth. [Photo: M0tty/CC BY-SA 3.0]

In 1921, Harry C. Tuttle began developing the telephone silencer in a small office near Union Square in New York City. From the 1920s through the late 1940s, Tuttle’s Hush-A-Phone Corporation pushed out the six-to-seven-inch devices to business people and professionals in the U.S. The device was particularly popular in Washington, D.C. and New York City, and even used to make private calls in Congressional Committee rooms, Columbia University law professor and network neutrality expert Tim Wu notes in his book, The Master Switch: The Rise and Fall of Information Empires.

“Tuttle and Beranek didn’t exactly consider themselves a threat to the Bell system,” wrote Wu, referring to MIT acoustics scientist Leo Beranek, who helped upgrade the device, and AT&T’s research division at the time. “Rather, their modest aim as independent, outside inventors was a minor improvement to the telephone handset, and an ungainly one at that.”

But their intent didn’t matter. AT&T wanted to make it known that it was the reigning phone system on the market. AT&T strategically bought out rivals, and blocked new and emerging companies by establishing regulations. In the late 1940s, the company enforced a blanket rule against all third-party phone extensions:

“No equipment, apparatus, circuit or device not furnished by the telephone company shall be attached to or connected with the facilities furnished by the telephone company, whether physically, by induction or otherwise.”

“The regulations in place were not made to help customers,” explains Thomas Hazlett, an economics professor at Clemson University in South Carolina. However, most people simply accepted the conditions of the market. “The monopoly idea was baked into the cake, and there wasn’t much controversy about the fact.”

The black, metal rectangular contraption of the Hush-A-Phone. [Photo: Marcin Wichary/CC BY 2.0]

It’s said that an AT&T lawyer came across a Hush-A-Phone displayed in a store window and brought one back to the company, wrote Stewart Schley in Business Insights: Essentials. T AT&T sent out cease and desist letters, while Bell repairmen began warning customers with Hush-A-Phones that if they didn’t stop using the devices, the company would stop providing service.

While other small companies may have just crumpled under the pressures, Tuttle defiantly took the issue to the FCC. The FCC held a two-week hearing in Washington, D.C., where Tuttle brought his lawyer, and two engineering experts, including Beranek.

AT&T argued that the Hush-A-Phone device posed a substantial harm to its telephone system, and that the company was committing fraud by selling a rather useless device. An engineer from Bell Labs was brought to the stand, and demonstrated a transmission loss of 13 decibels and receiving loss of 20 decibels with the Hush-A-Phone, which was greater than all the improvements made to the handsets over the last 20 years, he said.

AT&T’s president also claimed that third-party attachments could cause “power surges up the phone lines that might electrocute Bell repairmen and send them falling to their deaths,” wrote Wu. Upon cross-examination, it was concluded that nothing like this had ever happened before.

Hush-A-Phone refuted AT&T’s claims, and stated that the device actually could help mental health by reducing noise, and that privacy was necessary for their list of important clients. The two engineering witnesses conducted a series of tests that demonstrated that the words of the conversation could still be deciphered when using the Hush-A-Phone, while also maintaining secrecy.

An advertisement for the Hush-A-Phone. [Photo: Inside TWiT/CC BY-SA 2.0]

But the FCC could not come to a final decision at the end of the two-week hearing, and subsequently sat on the case for five years, until it finally ruled in favor of AT&T. A modern analogy to the ruling would be if AT&T was somehow able to ban putting protective cases manufactured by other companies on smartphones leased through AT&T, or if Apple was able to dictate which selfie sticks could be used with its iPhones.

Tuttle was hit hard by the drawn-out battle, as he financed the lawsuit himself. Still, he relentlessly appealed the FCC’s ruling and brought the case before the District Court. Finally in 1956, eight years later, the panel of federal judges overturned the FCC’s ruling: “To say that a telephone subscriber may produce the result in question by cupping his hand and speaking into it, but may not do so by using a device… is neither just nor reasonable,” the statement from the court noted.

Even though Tuttle eventually won, Hush-A-Phone couldn’t recover. The company advertised that Hush-A-Phone was now approved by federal tariff, but it was too late. Manufacturing couldn’t keep up with AT&T and Bell Lab’s 1960s product designs and handsets, and Hush-A-Phone was forced to shut down.

It was hardly a worthy rival for AT&T: after nearly three decades in business, the Hush-A-Phone Corporation had sold only around 125,000 units by the time of its final tally, in 1950, and was used by only a tiny proportion of telephone subscribers.

A candlestick phone on display at the Molalla Historical Museum. The Hush-A-Phone case helped pave the way for new additions to telephones. [Photo: PhotoAtelier/CC BY 2.0]

The triumph of the small Hush-a-Phone company marked the beginning of the collapse of AT&T’s monopoly. When the court contradicted the FCC and ordered AT&T to allow people to use the Hush-A-Phone and similar devices, “it was really important because that led the way for other devices like the telephone modem to be connected to the network,” says Jenkins.

The ways in which AT&T fought to gain to control over its customers are the same issues that we are dealing with today in battles over the open internet. Back then, “the regulatory system was so rigid and so costly that you wonder what we gave up,” says Hazlett. “What else could have come from the 1920s to the 1950s if we supported innovation?”

Hush-A-Phone’s non-legal legacy is scantier: there are no similar telephone privacy devices like the Hush-A-Phone in today’s market, says Jenkins, and taking calls in a crowded room where others might hear doesn’t seem to be much of an issue anymore.

Object of Intrigue is a weekly column in which we investigate the story behind a curious item. Is there an object you want to see covered? Email