This is one of hundreds of tidbits of information within the covers of a highly enjoyable book I’ve just finished reading, Exploding the Phone by Phil Lapsley. Through the course of five years, over 100 interviews and some 400 FOIA requests for FBI and other government files, Lapsley wove together an entertaining and engaging story of people who were arguably some of the first modern hackers. From the late 1940s until digital technology took over the telephone network in the late 1970s and in to the 1980s, there existed people – almost all teenagers – who routinely broke in to the back end of the telephone system to play, learn, explore and discover. They were nearly universally known as Phone Phreaks and a 2600 Hz sine wave was their key to the universe.
I’m just old enough to remember what the old telephone network actually sounded like. No, I don’t mean the sound of a person’s voice during the call, but the sounds OF the call – of the call’s progress through the network after your finger dialed the last digit of a long distance number. Today, the only thing most of us think about, if we think about it at all, is perhaps how crappy most wireless calls sound due to all manner of digital compression and noise. Today, you dial a number a continent away and it starts ringing on the other end almost immediately and there is nothing but silence in the intervening second or two. And assuming it’s a landline to landline call, it’ll likely be crystal clear and noise free as well. But back in the day, depending on how far away you were calling and how many pieces of telephone switchgear the call ended up being routed through, you would hear a brief symphony of sounds on the line as the multi-billion dollar machine that was the telephone system did its automated bidding to connect your one call, in among millions of others. While your connection was on its way, you might hear tones and clicks and strange clanging sounds, and at each punctuating set of hard sounds, the level of hiss and noise on the line would change – sometimes increasing, sometimes decreasing, changing in timbre and tone. You could tell that a process was taking place. In some ways it even seemed alive somehow. Once the call was connected it was sometimes a little noisy, sometimes you could just barely detect other conversations taking place way down in the hiss and there were other strange noises that floated through every so often. But, it was all we knew and when you were talking to grandma, it didn’t really matter anyway.
Exploding the Phone traces the rise of the post war automated telephone network as designed by Bell Labs and built by Western Electric. From the birth of the telephone system in the 19th century and half way in to the 20th in many places, your first step in making a call was to speak to a lady in the central office would would answer “number please” shortly after you took your phone off hook. Eventually, the engineers came up with a way to add some automation to this for local calls – the dial. It used to be big news when a community’s phones were switched over to dial service. Now all you would need an operator for in most cases was to make a long distance call. And in those days, depending on where you wanted to call, it could take as long as 15 minutes for the operator to get it through. She would call you back when she had your party on the line. Talk about personal service!
At the rate the customer base was growing, especially after WWII, AT&T engineers and executives knew that it would eventually be just physically impossible to recruit, hire, train and find room for enough human telephone operators to handle all the traffic. A method of automating the system so that long distance calls could also be made by direct-dial was needed. The methods that the Bell Labs Engineers and Scientists came up with to do this, especially in the days when vacuum tubes and electromechanical relays ruled the system – long, long before the transistor – were astounding at the time. But, in building the system the way they did, they unintentionally left the door open for some future customers, who were so inclined, to take over parts of the system from outside the central offices in the network. And in hindsight, it would seem they were able to do this by amazingly simple means. Today, all the call progress data moves on a separate CCIS network using SS7 (Signalling System 7 – phone engineers have never really been good at naming things interestingly). But back then, it all had to be done “in band” with audible tones that was able to pass through the voice circuitry anywhere in the network. So, if the officiall tones passed through the voice network, so could surreptitious signals generated at any phone line, anywhere.
So, Jobs and Woz and the illegal electronic devices? Well, OK, the devices themselves were not technically illegal. They once sold Blue Boxes that Woz manufactured. Their clientele included some fairly significant Hollywood luminaries. There was nothing directly illegal about using a Blue Box to get “behind the curtain” of the telephone network. However, one of the things that you could do once you were inside with a device like this was to make long distance phone calls without the telephone computers knowing you had – this is also known as “free long distance.” This is where the users of such devices ran afoul of wire fraud laws and this is where the telephone security people, and eventually the FBI, got involved. The magical Blue Box did two very simple things. First, it generated a pure 2600 Hz sine wave tone. Second, it was able to generate the Multi-Frequency (MF) tones that were only supposed to be used by the internal systems (or an operator) to route a call to a distant central office. Back then, if you placed a call to a toll free number and sent the 2600 Hz tone down the line, you could trick the distant switch in to thinking that you had abandoned the call and the distant switch would end the call and then wait. If the next thing you did was to send a specific set of MF tones down the line, you could get that distant piece of equipment to connect you basically anywhere in the world. But to your local phone company equipment, you were making a toll free 800 line call, so you would never see a bill for even one second of the time you were on the call.
What really started to get the feds concerned about all of this wasn’t so much the free long distance – after all, that was mostly up to the phone company to prosecute. It was that because of this gaping hole in the phone system, Phreakers had been known to electronically wiretap calls between FBI and other government offices, make calls to inside numbers at the White House and even access the secure military AUTOVON telephone system from the civilian network – and that included the tones and codes required to accomplish a “flash override” and knock any other traffic off the network in order to get your call through to, well basically anybody up to and including the President of the United States. Add to this that at least one anti-war group, in the age of Richard Nixon and Vietnam advocated stealing long distance in order to deprive the government of the revenue from a 10% excise tax on long distance calls that was pretty much specifically gear toward war funding, and it becomes clear why many elements of the government needed this whole issue to go away.
This is an epic story that covers a vast swath of time, technology and types of people. From the bookies in New York, Miami, Chicago and Las Vegas who discovered how to hide their long distance calls as early as the 1920s; to a blind teenager who could whistle a perfect 2600 Hz tone to seize a trunk; to the infamous Cap’n Crunch toy whistle that could do the same and that came in cereal boxes by the millions; to broken systems in the network that allowed unlimited voice conferencing for those who could find them; to arrests and court cases and jail time and the fact that at one time, Ma Bell routinely monitored something like 30 million phone lines at random and recorded, in one year, almost 1.5 million calls – all without court orders or warrants or any other legal basis for doing that – for the purpose of sniffing out toll fraud. In a system as huge and universal as the old Bell System, there are almost as many stories as there are phones.
Lapsley’s book tells the whole story in great detail, but without ever being dull, boring or “too technical”. I realize that I say that as a person who is technically minded and interested in the topic and the technology, but still, this book is eminently readable and accessible for all. Lapsley is a good story teller. There are large portions of the book that are real, honest page turners. He has the capability to draw the reader in and pace things along with just the right mix of fact, engineering discussion, direct quotes from the Phreakers themselves and even a fair dose of humor. After all, how can you not find some level of humor in a bunch of teenage boys who can remember every tiny detail of an article in the October 1971 issue of Esquire magazine that fully explained how a Blue Box worked and what you could do with it, but who can’t tell you what was on the cover of the magazine? That cover, by the way, was adorned by a drawing of a shapely young woman. Naked. On a swing …
This is a mostly untold story of a subculture within a subculture. In some ways it’s a treatise on the law of unintended consequences. In others it’s a celebration of human ingenuity, curiosity and spirit. It asks questions that are relevant to this day in this era of NSA data gulping and Snowden and the shattering of privacy and security.
In the end, it’s a story of amazing, smart, dedicated people doing incredible things. As all good stories should be.