An excerpt from Exploding the PhoneExploding the Phone

by Phil Lapsley

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Locke spent the next twenty-four hours in what felt like a scene from a 1940s detective movie: a barren room with nothing more than a wooden table, a chair for him, two chairs for his interrogators, and a bare lightbulb dangling from the ceiling. Sitting across from him, the FBI agent and the telephone security man worked hard to get him to confess to using the blue box.

Before smartphones and iPads, before the internet or the personal computer, a misfit group of technophiles, blind teenagers, hippies, and outlaws figured out how to hack the world's largest machine: the telephone system. The following is an excerpt from the new book Exploding the Phone written by Phil Lapsley and published by Grove/Atlantic, which tells the story of the "phone phreaks."

There it was again.

Jake Locke set down his cup and looked more closely at the classified ad. It was early afternoon on a clear spring day in Cambridge in 1967. Locke, an undergrad at Harvard University, had just gotten out of bed. A transplant from southern California, he didn’t quite fit in with Harvard’s button-down culture – another student had told him he looked like a “nerdy California surfer,” what with his black-framed eyeglasses, blond hair, blue eyes, and tall, slim build. Now in the midst of his sophomore slump, Locke found himself spending a lot of time sleeping late, cutting classes, and reading the newspaper to find interesting things to do. Pretty much anything seemed better than going to classes, in fact. ("Jake Locke" is a pseudonym).

It was a slow news day. The Crimson, Harvard’s student newspaper, didn’t have much in the way of interesting articles, so Locke once again found himself reading the classified ads over breakfast. He had become something of a connoisseur of these little bits of poetry – people selling cars, looking for roommates, even the occasional kooky personal ad probably intended as a joke between lovers—all expressed in a dozen or so words.

But this ad was different. It had been running for a while and it had started to bug him.

WANTED HARVARD MIT Fine Arts no. 13 notebook. (121 pages) & 40 page reply K.K. & C.R. plus 2,800; battery; m.f. El presidente no esta aqui asora, que lastima. B. David Box 11595 St. Louis, MO 63105.

Locke had seen similar classified ads from students who had lost their notes for one class or another and were panicking as exams rolled around. They often were placed in the Crimson in the hopes that some kind soul had found their notes and would return them. Fine Arts 13 was the introductory art appreciation class at Harvard, so that fit.

But nothing else about the ad made any sense. Fine Arts 13 wasn’t offered at MIT. And what was all the gibberish afterward? 2,800? Battery? M.f., K.K., C.R.? What was with the Spanish? And why was somebody in St. Louis, Missouri, running an ad in Cambridge, Massachusetts, looking for a notebook for a class at Harvard? Locke had watched the ad run every day for the past few weeks. Whoever they were, and whatever it was, they clearly wanted this notebook. Why were they so persistent?

One way to find out.

Locke looked around for a piece of paper and a pen. He wrote: “Dear B. David: I have your notebook. Let’s talk. Sincerely, Jake.”

He dropped the letter in the mail on his way into Harvard Square to find something interesting to do.

An envelope with a St. Louis, Missouri, postmark showed up in Locke’s mailbox a week later. Locke opened the envelope and read the single sheet of paper. Or rather, he tried to read it. It wasn’t in English. It seemed to be written in some sort of alien hieroglyphics. It was brief, only a paragraph or so long. The characters looked familiar somehow but not enough that he could decipher them.

Locke showed the letter to everyone he saw that day but nobody could read it. Later that evening, as Locke sat at the kitchen table in his dorm room and stared at the letter, trying to puzzle it out, one of his roommates came home. Shocked that Locke might actually be doing something that looked like homework, his roommate asked what he was working on. Locke passed the letter across the table and told him about it.

His roommate took one look and said, “It looks like Russian.”

Locke said, “That’s what I thought. But the characters don’t seem right.”

“Yeah. They’re not. In fact ...” His roommate’s voice trailed off for a moment. “In fact, they’re mirror writing.”

“What?”

“You know, mirror writing. The letters are written backwards. See?”

Locke looked. Sure enough: backwards.

Locke and his roommate went to the mirror and transcribed the reversed lettering. It was Cyrillic – Russian letters. Fortunately, Locke’s roommate was taking a Russian class. They sat back down at the table and translated the letter.

“Dear Jake,” the letter read. “Thank you very much for your reply. However, I seriously doubt that you have what I need. I would strongly advise you to keep to yourself and not interfere. This is serious business and you could get into trouble.” Signed, B. David.

Locke sat back. Someone had put a cryptic ad in the newspaper. He’d responded. They sent him a letter. In mirror writing. In Russian. In 1967. During the cold war.

Spy ring.

It just didn’t get much cooler than this, Locke figured. Intriguing. Terrifying, even. And far, far better than going to class.

A blue box circa 1961-1970s. Photo: Ed Turnley

Locke mailed his reply that day – in English, and not in mirror writing. “Dear B. David: Actually, I do have your notebook and I would like to talk to you. Sincerely, Jake.”

Four days went by before the mailman brought Locke an odd letter, a piece of card stock folded in half and taped at the top. The fold line was perforated so that it could be torn in half. The writing was in English this time.

“Dear Jake, if you have the information I need, you should be able to complete the other half of this card and mail it back to me. Then we can continue our discussions. Sincerely, B. David.”

Locke looked at the other half of the postcard. It had a handful of questions on it:

Complete the following sequence: 604, 234, 121, ___

What does M.F. stand for?

What equipment were the students at Harvard and MIT using?

Huh?

Locke spent every waking hour over the next several days working on the postcard questions. The numbers repeated over and over in his mind: 604, 234, 121 ... 604, 234, 121 ... 604, 234, 121 ...

604-234-1212.

A phone number? It wasn’t directory assistance – Locke knew that would have been 555-1212 – but it sort of sounded right. Worth a shot, anyway. He picked up the phone and dialed. A woman’s businesslike voice answered on the first ring.

“Cleaner clean,” she said.

“Excuse me?” said Locke.

“Cleaner clean inward,” the woman repeated, more distinctly this time.

Locke hung up. He stared at the phone. Cleaner clean? Inward?

Where was area code 604, anyway? The phone book said British Columbia. And where was that? Western Canada. Locke looked around his dorm room, found an atlas, and flipped to the page on British Columbia. He scanned the map. The big cities had names he recognized, names like Vancouver and Prince George. The smaller towns had less familiar names. Names like Kamloops. Squamish. Quesnel. Chilanko.

Kleena Kleene.

Excerpt: Long-Distance operators at "cord boards" circa 1945. Well until mid-century the operator's hands, arms, and brains were the workhorses of long-distance telephone switching. Photo: The National Archives

At dinner that nightLocke mentioned his phone call to Steve, another of his roommates. Steve said, “Huh. That’s interesting. My girlfriend Suzy is an inward.”

“What? What’s an inward?” asked Locke.

“It’s some kind of special telephone operator. You should talk to her, she might be able to help you figure some of this stuff out. She lives over in Revere. Give her a call.”

Locke did. Suzy explained that an inward is an “operator’s operator.” When an operator needs assistance in making a call, she calls the inward operator for the destination city. The inward operator then completes the call to a local number.

“So how do I call an inward?” Locke asked her.

“You can’t. Inwards have special phone numbers that only operators can dial. If you wanted to call the New York inward, you’d have to dial something like 212-049-121. So 121 is what gets you the inward, and 049 is a routing code inside of New York, and New York is the 212 area code. But you can’t dial numbers like 049 or 121 from a regular phone.”

Locke explained that he seemed to have found a way to call an inward operator from his regular phone by dialing 604-234-1212.

“Well,” Suzy said, “I’m mystified. You shouldn’t be able to. I don’t know, maybe you found a glitch. But here’s how you can tell. Call them up and ask them to complete a call to somebody. If they’re really an inward, they’ll be able to do it no problem.”

“I don’t know anybody in Canada,” Locke said.

“That’s okay. An inward can call anywhere. And we sometimes get calls from the test board within the phone company asking us to complete calls to places for testing purposes. Just tell them you’re with the test board. Be confident and self-assured and act like you know what you’re doing and they won’t give you any trouble.”

“Okay. I’ll try that. Hey, any idea what ‘M.F.’ might stand for?”

“Well,” Suzy replied, “it could be multifrequency.”

“Multifrequency. What’s that?” Locke asked.

“It’s the system that operators use to make calls. It’s kind of like those touch tones used for push-button dialing, but it sounds different.” Locke’s dorm phone was rotary dial, but he knew what touch tones were – they had been introduced just a few years earlier.

“Okay. Hey, thanks, Suzy.” They said good-bye. He hung up.

Locke picked up the phone again and dialed 604-234-1212. Once again the businesslike female voice answered.

“Kleena Kleene inward.”

“Hi, uh, yes,” Locke said. “This is the test board. Could you connect me to 619-374-8491, please?”

“One moment.” There was a pause. The long-distance hiss got louder. A click. Another pause. More hiss. Another click. Then a ringing signal.

“Hello?” It was his friend Dave in San Diego.

Locke chatted with his friend for a few minutes and then hung up. He felt as if he were floating. It seemed magical. “Act like you know what you’re doing and they won’t give you any trouble.” It worked!

Blue Boxes Circa 1961-1970s. Photo: Ed Turnley

Two postcard questions down. One left: “What equipment were the students at MIT using?”

Once again, another roommate came to Locke’s rescue – ­fortunately, Locke lived in a suite and had lots of roommates. “We’re talking about phones and MIT students, right? I remember an article in the Crimson about a year ago about some MIT students who got in trouble for playing with the telephone. Could that be it?”

“Maybe,” said Locke. “But how am I gonna find an old copy of the Crimson?”

“The library?” his friend suggested.

This was a challenge. Locke had never been to the university’s library before.

Locke was surprised to find it was close to his dorm and that other students seemed able to direct him there. Soon Locke was flipping through page after page of old Crimsons. An hour later, in an issue from almost a year earlier in 1966, he found what he was looking for.

FIVE STUDENTS PSYCH BELL SYSTEM, PLACE FREE LONG DISTANCE CALLS Five local students, four from Harvard and one from M.I.T., spent eight months making long distance and international phone calls as guests of the Bell System before they were finally discovered. The telephone company accepted the news without bitterness, however, merely impounding the 121-page Fine Arts 13 notebook that contained the records of their “researches” and requiring them to submit a full report, which ran to 40 double-spaced pages, of what they had done.

Mesmerized, Locke read on, the words from the classified ad running through his head. The article described how, starting in 1962, the students had used inward operators – including one in Kleena Kleene – to complete calls all over the world. It tantalized with an infuriatingly brief description of how it was possible to build an electronic device to control the telephone system for “$50 of common electronic components.” The article concluded abruptly, stating that the students were caught in April 1963 when a telephone company employee turned them in.

Locke was elated. Pieces were falling into place, and now he had enough to respond to B. David. But the article was short on details. He needed to find out more. He needed to talk to the original Harvard and MIT students. Locke jotted down the name of the article’s author, another student at Harvard.

The next day he filled out the reply postcard and dropped it in the mail to B. David. Then he called the Crimson reporter to pump him for details. The reporter wasn’t very helpful. He didn’t know the names of the Harvard or MIT students, he said, and it turned out that he had gotten most of his information from an article in the Boston Herald. He had then talked to the Herald reporter to get some additional context.

“Didn’t the Herald reporter know the names of the students?” Locke asked.

“Oh, sure, but he wouldn’t give them to me. And I doubt he’ll give them to you either,” the Crimson reporter replied.

Back to the library. Locke dug up the Herald article. It described the Harvard and MIT students making calls to the president of Mexico and gave a name – “blue box” – to the electronic device that had allowed them to control the telephone network. It spoke of their staying up all night, of spending eighty hours a week on their research, of dialing ten thousand numbers over two to three days to find the information they needed. It even said the students were questioned by FBI agents who thought they were stealing defense secrets.

Locke looked up the telephone number for the newspaper. Be confident and self-assured and act like you know what you’re doing. He drew a deep breath, picked up the phone, dialed the Herald, and asked to be connected to the reporter who wrote the article. When the reporter answered, Locke politely explained who he was and what he was looking for.

“This is Special Agent Stevenson with the FBI Boston Field Office. We’ve had a report that there has been some new activity related to an incident that occurred a few years ago with some Harvard and MIT students misusing the telephone system. We’re trying to reach them to talk to them about this but we don’t have current contact information for them. I saw your article about them from a year ago or so. Do you have telephone numbers for any of them?”

Not a problem, the reporter replied. He’d be happy to help.

Before Locke had achance to call any of the students his phone rang. It was B. David and he wanted to know about the Fine Arts 13 notebook. Oh, yes, that notebook: the one that Locke didn’t actually have. Locke did his best to keep up the charade. Well, he admitted, he wasn’t actually one of the Harvard or MIT students but he knew them. He was a friend of theirs. He had participated in some of their “research.”

B. David grilled him. It quickly became apparent that Locke didn’t know as much as he was claiming. As Locke would later recall, “You can only fake things so far before they begin to crumble.” Locke admitted the truth.

Surprisingly, B. David wasn’t mad, and now that the cat was out of the bag the two had a pleasant conversation. B. David explained that there was an informal network of telephone enthusiasts like himself, and that he had been trying to reach the Harvard and MIT students to talk to them about their exploits. “Welcome to our world,” he said. Locke asked for pointers. B. David demurred on details: “I don’t want to give you too much information. I will tell you one thing, though: look for missing exchanges. Look for patterns. I’ll give you a call back in a few weeks to see how you’re doing.”

This all seemed fascinating to Locke. He called the former MIT student – now living in Berkeley, California – whose number he had gotten from the Herald reporter. The student was friendly enough but, like B. David, was also reluctant to provide much information. The MIT student explained that he and his friends had been caught and interrogated by the FBI, although not actually prosecuted. He stressed that Locke could get in trouble playing with this stuff and that Locke should stay away from the whole thing. Locke pressed him for more information. Finally the MIT student told him, “If you really want to find out more, everything you need to know is in the library.”

Great, thought Locke, a third trip to the library.

But what library would have the sort of information he was looking for? Some research led him to the physics library and something called the Bell System Technical Journal. The one term Locke knew to look up was “multifrequency.” From the journal’s index he quickly located an article from the November 1960 issue titled “Signaling Systems for Control of Telephone Switching.” It was technical but not so technical that Locke couldn’t understand a good chunk of it. It laid out in detail exactly how certain aspects of the telephone system worked, including the multifrequency signaling system. This article plus the Crimson and Herald stories, as well as his conversations with B. David and the former MIT student, gave him everything he needed to get serious about this stuff.

Locke started to spend a lot of time on the telephone. “Look for missing exchanges, look for patterns,” B. David had told him. Locke knew that an exchange was the first three digits of a local telephone number. By making a careful study of the telephone book and doing a lot of dialing, Locke discovered that there were indeed missing exchanges in the downtown Boston area. When Locke found a missing exchange, he would start dialing all the telephone numbers in it. All ten thousand of them.

Weeks later Locke had three things to show for his efforts. The first was an indelible black circle around his index finger from his repeated dialing. Second was four livid roommates: because Locke was constantly on the phone, none of them could make or receive phone calls. But third was a collection of some very interesting telephone numbers. Some of these were odd test numbers, numbers that made weird beeps, boops, clicks, and tones. More interesting were so-called party lines. These were typically vacant number recordings (“We’re sorry, you have reached a nonworking number ...”) whose audio levels were very low. All the callers to one of these numbers would be connected, and because the volume of the recordings was so low people could talk over the recordings. As a result, they served as primitive conference calls at a time when such things were unheard of.

Most interesting, though, was that several numbers went to inward operators in various places.

Locke’s obsession grew. He decided he wanted to build one of these mystical “blue boxes” so that he, too, could directly control the telephone network. That meant he’d need to build electronic oscillators, circuits that would make musical tones. But Locke didn’t know anything about electronics. Looking for patterns and missing exchange numbers was one thing; electronic circuit design was something else. Locke got a friend of his to introduce him to a graduate student in the physics department in order to persuade him to help build the oscillator circuits he needed for his blue box.

“What do you need them for?” the grad student asked.

Be confident and self-assured and act like you know what you’re doing. “I’m a biology major and I’m studying the effects of high-­frequency audio oscillations on fruitfly germination.”

The grad student raised an eyebrow but helped Locke anyway.

Locke started haunting the electronics stores in Cambridge, looking for parts and guidance on assembling his blue box. Before long he linked up with students at MIT in the Tech Model Railroad Club, or TMRC, near the Kendall Square T Station. The TMRC was home to one of the most technically sophisticated model railroad setups in the country, possibly the world. MIT students had laid out some six hundred feet of track simulating ten scale miles of railroad amid painstakingly detailed scenery. The trains were controlled by a fantastically complex switching system based on many of the same principles as the telephone network. Indeed, the telephone company had donated equipment to the club for just this purpose, and the club’s faculty adviser was in charge of MIT’s telephone system, so it was not surprising that model train operators at TMRC used a telephone dial to select the train to be controlled. It was a veritable breeding ground for telephone enthusiasts.

With help from the more electronically knowledgeable students at MIT, and only a few soldering iron burns, Locke was able to piece together a blue box. By now Locke had been told by enough people that he could get in trouble for using his blue box and that he should be careful. So Locke was careful – when it was convenient, anyway. He used his blue box from the pay phone in his dorm quite a bit, as well as from friends’ houses. As Locke figured it, the only thing he was doing with it was using it to learn about how the phone system worked. He didn’t even really know anybody far away he wanted to call, so it wasn’t like he was racking up thousands of dollars in free long-distance calls. He just couldn’t imagine that anyone cared about his activities that much.

Incredibly enough, some people did care, as Locke learned upon returning to his dorm room in June 1967, just three months after seeing the Fine Arts 13 ad in the Crimson. He knew he was in trouble from the moment he walked in the door: waiting for him in his living room were three men. One of them was the crestfallen house master, the Harvard professor who was the head of Locke’s dorm. Locke didn’t know the other two, but he did notice that one of them was wearing a trench coat – strange, given that it was a warm summer day.

“The jig’s up, Locke,” the house master said.

Trying to stall for time, Locke asked, “Which jig?”

Based on the reactions of his three visitors, Locke surmised this was the wrong thing to have said.

“You know which jig we’re talking about, Locke,” said one of the men. “The telephone jig. We’ve been through your things.” He held up Locke’s blue box. “We need to talk.”

One of his visitors turned out to be from the telephone company, AT&T security. The other introduced himself as a special agent from the FBI’s Boston Field Office. They asked Locke to come downtown with them. The FBI agent told him that this was a very serious matter, that they had some questions they wanted straight answers to, and that they would arrest him if he didn’t cooperate.

Locke spent the next twenty-four hours in what felt like a scene from a 1940s detective movie: a barren room with nothing more than a wooden table, a chair for him, two chairs for his interrogators, and a bare lightbulb dangling from the ceiling. Sitting across from him, the FBI agent and the telephone security man worked hard to get him to confess to using the blue box to make free telephone calls. Despite being scared to death Locke denied everything. He didn’t know what they were talking about, he said.

After several hours of questioning, he finally admitted that yes, the blue box was his, but that he had used it only to learn about the telephone network. Locke expected them to start grilling him about how many free calls he had made, but his interrogators shifted focus. They wanted to know who had given him the technical information necessary for him to build a blue box. He explained that he had seen an article in the Boston Herald and then found the Bell System Technical Journal article and gone on from there. In other words, there wasn’t anyone else; he had been all on his own. It took a long time, but he managed to convince them of his version of events.

Again the questioning shifted course. Okay, they said, you figured out this stuff on your own. Fine. Now tell us who you’ve been selling the boxes to.

Locke was flummoxed. Selling the boxes? What boxes? He had built only the one, and he hadn’t sold it to anyone. The FBI agent grilled him. They were sure he had been selling them – or at least supplying them – to others. To whom, they wouldn’t say. After hours of back and forth, Locke was able to get across that it was just him, there was just the one box he had built, and he hadn’t been selling them. (In retrospect, Locke says he is glad he never thought of this. “The idea of selling blue boxes had never occurred to me ... fortunately! It’s not a bad idea.”)

Locke spent the evening in the care of the FBI. In the morning he was told he could leave, but only after he prepared a written report describing what he had done and the techniques he had used. He spent the morning writing this report.

As he was leaving, Locke turned to the man from the phone company. His face slipped into a grin. “By the way,” he said, “I’m not doing anything for the summer. You guys wouldn’t happen to have any job openings, would you?”