Unlocking Ma Bell: How phone phreaks came to be

In "Exploding the Phone," Phil Lapsley writes an entertaining and educational history of the people who hacked the original phone networks. Lapsley talked to CNET about his book.

Daniel Terdiman Former Senior Writer / News
Daniel Terdiman is a senior writer at CNET News covering Twitter, Net culture, and everything in between.
Daniel Terdiman
8 min read

Imagine a day when it cost an arm and a leg to use the phone, especially for long-distance calls. Then imagine that buried deep within the telephone network infrastructure was a flaw -- a hole that allowed those who were aware of it, and capable of exploiting it, to make all the free calls they want.

'Exploding the Phone' author Phil Lapsley Margaretta K. Mitchell

These days, phone calls are free -- or nearly so -- and hackers put their energies into computer networks, jailbreaking iPhones, and other more modern pursuits. But back in the 1950s and 1960s, a new group of people emerged, people who were fascinated by phones, telephone networks, and who often just wanted to see how many free calls they could make. Over the years, the roster of the so-called "phone phreaks" grew to include some very famous people: Apple co-founders Steve Jobs and Steve Wozniak, and John Draper (aka Captain Crunch).

Their tools also became part of the lexicon -- blue boxes and black boxes -- despite the fact that today, the number of people who know what those devices could do is rapidly dwindling.

Just in time to ensure that the tale of the phreaks is told before it's too late is Phil Lapsley, who has just published "Exploding the Phone: The Untold Story of the Teenagers and Outlaws who hacked Ma Bell." A deep dive into how the telephone network evolved, and how the phreakers came to launch their assaults on the integrity of the networks, the book is at once enjoyable and educational. Especially in an era where hackers are among the biggest stars around. Yesterday, Lapsley sat down with CNET for a 45 Minutes on IM interview about the storied history of the phreaks.

Q: Why did you want to write this book?
Phil Lapsley: I learned about phone phreaking in 1978 or so, and it seemed to me that it was the predecessor to computer hacking. Later, when I became an electrical engineer and computer person, I always felt there was this interesting and unexplored history out there.

In 2005 I was reading the Wikipedia entry on phreaking and I was sure half of it was wrong. So, I started doing research. My main curiosity was, who were the first phone phreaks, when did they start showing up, and what made them want to do it?

What is phone phreaking?
There are two definitions of phone phreak. One is somebody who is obsessively interested in learning about, exploring, and playing around with the telephone system. The other is somebody who is interested in making free phone calls (think back to when phone calls were actually expensive and this makes more sense).

When I talk about phone phreaks, I'm generally talking about people who were exploring the telephone system out of curiosity and figuring out how it worked. This was particularly true of the early phreaks (say in the 1960s); it became less true as time marched on, and more phreaks were interested in just making free phone calls.

You begin with a reference to the "Fine Arts 13" notebook. What was that? And why was it important?
The first chapter in the book follows the path of a Harvard sophomore named Jake Locke (a pseudonym; he's a guy who has gone on to greatness since that time and didn't want his real name used in the book). Locke ends up spotting a classified ad in the Harvard student newspaper that leads him down a rabbit hole, trying to find these kids at Harvard in 1962 who wrote something called the Fine Arts 13 notebook. In that notebook they recorded all of their telephone "researches" (as they called it) as they were trying to figure out how the telephone system worked, just by dialing numbers and talking to people and putting clues together.

One thing that seemed so strange, given today's corporate paranoia, is how open AT&T was with the technical details of their network. How odd is that, from today's perspective?
One of the challenges I had in writing the book was conveying a sense of what things were like back then. For example, today, if you want to learn how the phone system works, you just do some Googling and bang, it's there for you to read about. It simply wasn't like that in the 1960s and 1970s: information was vastly harder to come by. But there's a flip side.

Today, we assume anything a company does will be a trade secret, and there will be non-disclosure agreements and such to protect intellectual property. While that was generally true back then, too, it wasn't quite the case for AT&T, the telephone company. AT&T was a private company but was a government-regulated monopoly, and didn't really have any competitors. In that environment, you don't need to be quite as careful with your secrets. Indeed, some of AT&T's published journals (The Bell System Technical Journal, Bell Labs Record) were partly for well-deserved bragging rights -- hey, look at the cool stuff we did! It's a very different world. Maybe there is a Google Labs Technical Journal, but if there is, I suspect you have to work there to read it.

You wrote in the book about AT&T building the largest machine on earth, which extended to the entire surface of the planet. Can you explain that idea?
In the 1920s and 1930s, AT&T had a manually-operated long distance network requiring multiple operators plugging cords into jacks on a switchboard to get your call through. Then AT&T started pushing for automation, first with local calls -- so you could dial a local number and automatically connect -- and eventually spreading to long distance dialing.

This was an incredibly tough problem to solve in the 1930s and 1940s: the idea of building an automated switching machine that could somehow figure out how to automatically route your call across the country. It needed to be able to route through intermediate cities, and it needed to figure out back up routes if the first route it tried failed. And it needed to automatically bill you for it. It was a network of machines made up of relays and vacuum tubes. The computer hadn't even been invented yet, much less the transistor.

But AT&T and Bell Labs persevered and built this giant network of automated switching machines. And that's why the phrase "the largest machine in the world" is so apt: all of these thousands of switching machines, strung out all over the U.S. (and later the rest of the world) really did form one giant machine, one of the earliest special purpose computers.

You write about a lot of different phreakers. Was there one who was considered the most important?
Probably that would be Joe Engressia. This was a guy who had been obsessed with phones since he was three or four years old. Engressia was born blind and kind of eccentric but was also just incredibly gifted and bright. He learned everything he could about the telephone system and by the time he was 8 or 9 years old was confounding adults who worked for the phone company with his knowledge.

In college in 1968, he got famous for getting in trouble for whistling -- yes, whistling, like with his lips -- free phone calls for his classmates. He almost got kicked out of school. The news media picked up on the story and he became a focal point for a network of phone phreaks that was forming. Engressia was a natural person to be the center of the network because he was smart, knew a whole lot about phreaking and telephones, and was simply a nice, easy to talk to, open guy. Ron Rosenbaum wrote an article for Esquire Magazine about phone phreaks in 1971 describing Engressia as the 22-year-old "Grandaddy of the phone phreaks." I think that's apt.

Clearly, some of what the phreakers were doing was either illegal, or borderline illegal. But at the beginning, at least, courts were fairly lenient in phreaking cases. Why do you think?
Playing around with the phone wasn't (and isn't) illegal. But making free phone calls was. And a lot of these phone phreaks, even the ones who were "just curious," crossed the line into illegality when they made free phone calls to talk to their friends. At the start, in the 1960s, AT&T mostly just slapped these kids on the wrist and tried to scare them into stopping -- the term they used was a "deterrent interview." I.e., "Knock it off, kid, or we'll send the FBI after you." There were a couple of reasons for this.

When AT&T first learned its network was vulnerable, it wasn't sure how widespread the problem was or how seriously to take the threat. It also had a public relations problem: it looks bad when you prosecute college students who just seem clever and curious. And especially so when some of them are blind. Plus, every time it did something publicly about the phone phreaks, there would be newspaper articles and that generated more phone phreaks. Finally, it often wasn't clear what law the kids were breaking. AT&T really wanted a clear federal law that made this stuff illegal, but it wasn't clear (at least during the 1960s) that any such law existed.

But by 1972 there was a federal law that did apply, and AT&T had tested it in court. Phone phreaking was out in the mainstream, so in the early 1970s the phone company became much more serious about criminal prosecution.

What was Greenstar?
Greenstar was AT&T's toll fraud surveillance system. When AT&T first learned in 1961 that its network was vulnerable, hey had no idea how big the problem was, and so they didn't know how much money to spend to fix it. Was this a thousand dollar problem, or a billion dollar one?

Greenstar answered this question, starting in 1964, and by 1970 it was installed in five cities. It silently monitored long distance toll calls, looking for evidence of fraud -- somebody using a "blue box" or "black box" to make a free call. When it found a suspicious call, it silently recorded it, and trained human operators had to decide if the call was fraudulent. Greenstar monitored some 33 million American telephone calls, and secretly tape recorded 1.5 million of them.

Was it legal?
We'll never know for sure, because that would have required a court case involving it. AT&T very carefully keep Greenstar out of the lime ight (and out of court). Greenstar came to light in 1975 and there were congressional hearings. AT&T offered a vigorous defense, saying it was legal and was the only way they could get a handle on the fraud problem. The Congressional Research Service studied the matter and the best they could do was conclude that it was "unclear" if the system was legal or not.

And what was the Telephone Crime Lab?
The Telephone Crime Lab was a small department at Bell Laboratories that dealt with crimes involving the telephone. This was something that AT&T and Bell Labs initially provided as a service to the government and FBI in the 1960s, since Bell Labs had the best telephone engineers and technicians in the country, and the FBI was increasingly seeing high tech crimes that involved the telephone, or in some cases, audio recordings. One of the people I interviewed for the book, Ken Hopper, was a Distinguished Member of the Technical Staff at Bell Labs. He recalled that the Telephone Crime Lab started off as a "5 percent job" (i.e., something that would take up 5 percent of one employee's time) and within a few years was close to 100 percent of several employees' time. They did everything from helping out with de-noising audio tapes to investigating phone phreaks.